So, to start things off, i booted up Crystal on the VC for the first time, and decided to pick Totodile, i wanted to have a relatively fresh run and wanted to use Pokemon that i haven't used in an ingame playthrough for the most part, and i decided that my first teammate was going to be Bellsprout! Not only because i wanted a fresh new experience, but because i saw it was D rank when checking this thread for a general idea of what's good ingame and after a bit of theorycrafting it didn't really make sense to me, i decided i might as well test it out myself to see if my theorycraft could be put into practice.
I caught Bellsprout at route 31, at level 5. This is the first thing that really makes me think of Bellsprout (C) as the best non starter Grass-type in the game, availability. Bellsprout is easily obtainable early on in the game, before you reach Violet City even, and it has both a high encounter rate (20%) and catch rate (255) to boot! Catching it should be no problem at all. To level Bellsprout up and get things going, i simply went to dark cave and trained against the geodude in there for a few minutes, i started off training it on route 31 since i overestimated zubat's encounter rate in dark cave, but after realizing geodude was far more common, i simply switched spots and kept training from there. Even with that little hiccup, getting Bellsprout to level 11 (both the level of my Totodile at the time without any real grinding and the level it learns wrap by level up) only took about 20 minutes.
Once Bellsprout learned wrap, i decided that it'd be a good idea to use it against the sages in the sprout tower, considering it 4x resists its own vine whip and outlevels pretty much every other Bellsprout there, it seemed like a pretty good idea to me, especially because Totodile doesn't exactly have the best matchup against them itself (i had the level advantage, but i wanted to play it safe due to being uncertain on how consistently i could KO the opposing Bellsprout before they could get a Vine Whip in). Bellsprout ended up soloing the entire sprout tower on its own (none of the Hoothoot have any flying-type moves, i didn't really have anything to fear honestly) and i got flash for future use. Totodile handled Falkner on its own, it didn't seem like a good idea to throw Bellsprout against a Pidgeotto with Gust.
After finishing up in Violet City, i made sure to pick up the Miracle Seed on the way out, i was well aware it'd take a while for Bellsprout to learn a Grass-Type move stronger than Vine Whip and thought that picking up the seed and having Bellsprout hold it would help out a bit. Bellsprout was fairly useful as i went through Route 32 and Union Cave. I was aware that my starter could handle most of the Rock and Ground types encountered around this point such as Geodude, Onix, and Wooper, but i just wanted to test Bellsprout out and see what it could do.
Bellsprout wasn't particularly useful during the Team Rocket encounter in Slowpoke Well, but it was surprisingly solid when it came to the other activities around the area. It took out Silver's Bayleef for me, it took a while, but it was never in any real danger due to the 4x resistance it had to Razor Leaf. By this point, Bellsprout had hit level 15 and learned Sleep Powder, one of the other big positives the Bellsprout line has. Sleep Powder's an excellent move ingame for both catching new team members and crippling opposing Pokemon so you can take them down. Being able to put a key opponent to sleep means that the Bellsprout line can still potentially be useful, even in "bad" matchups vs important trainers. I had my starter (i'm pretty sure Totodile evolved somewhere around this point, but not 100% sure when) take out all the gym trainers in Azalea gym, and took a look at Bugsy's team. I noticed that Bugsy's Scyther didn't really have anything that was *too* threatening to Bellsprout, and that his Metapod/Kakuna were absolute setup bait, so i decided to do the unthinkable and tried to solo Bugsy with Bellsprout. To my surprise, i actually managed to do it easily! The combination of Sleep Powder and Metapod's low damage output let me set up to +6 against it quite easily. Sleep Powder allowed Bellsprout to put Scyther to sleep before it could use Fury Cutter too many times in a row, stopping Scyther from doing *severe* damage to Bellsprout easily. Eventually repeated +6 Vine Whips and residual damage from Wrap did Scyther in, and Bellsprout won the Hive Badge on its own!
On the route to Goldenrod, Bellsprout both learned Stun Spore (useful for similar reasons to Sleep Powder) and evolved into Weepinbell! Notably, Weepinbell's offensive stats are higher than Meganium's, meaning that even when it's unevolved, it can put in quite a bit of damage. On route 34, i made sure to get Picnicker Gina's number so i could get a Leaf Stone to evolve Weepinbell into Victreebel later. I'm aware of the exploits to get the stones from Pokegear calls more easily, but i wanted to do this run completely glitch/exploit free, and i was lucky enough to have Gina call me with a Leaf Stone when i left the game on without paying attention to it for 10 minutes, so yeah. I decided to battle all the trainers in the area surrounding Goldenrod just to get some extra experience before facing Whitney, along the way, Weepinbell learned Acid.
Alright, so once Weepinbell learned Acid, i could've evolved it right then and there and i probably would've been fine, but i thought things over a bit and decided that i wanted to wait a while before evolving Weepinbell for two reasons. The first was that i wanted to wait until Weepinbell learned Razor Leaf before evolving it, which is pretty late, but still more than attainable pre-kanto without any significant grinding or anything, and the second was that i simply wanted to see how well Weepinbell would perform throughout the game without evolving it. Theoretically even if you evolved Weepinbell right here and now, it'd be possible to get a decent moveset on it before the pokemon league, but i'll get to that later.
Onto Whitney, Croconaw took out Clefairy quite easily, and when met with Miltank, i decided that my gameplan would be to use Weepinbell to paralyze Miltank, both to slow it down and for the chance for full paralysis to stop Miltank during Rollout, resetting its power. I had to use an Oddish i caught in Ilex Forest as death fodder because of some bad luck with Attract, but Weepinbell managed to both paralyze Miltank, and with a bit of luck, defeat it.
Weepinbell really shined on the way to Ecruteak, simply because Sleep Powder made catching Sudowoodo (who i had planned out as the third member of my team at this point) that much easier. Once i got to Ecruteak, i got Surf from the Kimono Girls and went into the burnt tower to activate the event for the legendary beasts. Once again, just like before, Weepinbell did a very good job of shutting down Silver's Bayleef during the match. After the beasts started roaming, i made my way to Route 38 and caught a Miltank for my team. From there, i fought the trainers on the way to both Olivine and Mahogany to level it up so it was on par with the rest of my team. Afterwards, i went and fought Morty, Croconaw really did most of the work throughout the gym, although Weepinbell paralyzed Gengar, making it easier to take down, by the time the gym battle was over Croconaw evolved into Feraligatr.
OK, so now, something really important. If you're using the Bellsprout line on your ingame team, i'd highly recommend doing the events at Mahogany town before *anything* else after beating Morty. Why? After you drive all the Team Rocket members out of Mahogany, you can get the TM for Sludge Bomb. Giving Weepinbell Sludge Bomb makes it an absolute monster for pretty much the rest of the game, and i'd highly suggest obtaining it as early as possible. After adding a Drowzee i caught early game onto my team, I arrived at Mahogany town and caught the Red Gyarados to get the event rolling (once again, Weepinbell made catching Gyarados pretty painless with Sleep Powder). I didn't really use Weepinbell much against Team Rocket due to type matchups and me wanting to raise Drowzee up (in hindsight, getting the Return TM at Goldenrod might've made Weepinbell a bit more useful vs the Poison-types that Team Rocket has, might be worth getting if any of you guys want to give it a shot), but once all of that was finished, i was able to get the TM for Sludge Bomb and teach it to Weepinbell immediately.
Afterwards, i went to Cianwood city so i could get Chuck's badge and get the SecretPotion for Amphy (made sure to go to the lighthouse beforehand to activate the secretpotion event and to get some levels on my team, especially since my new Drowzee still needed some TLC). Weepinbell absolutely destroyed routes 40 and 41, even the Tentacool on the route that resisted the move ended up getting OHKOed by it. From what i remember, only a handful of Pokemon on the route were able to survive a Sludge Bomb at all, and i didn't use a single Pokemon other than Weepinbell on the way there. Once i got to Cianwood, i picked up the SecretPotion, i fought Eusine. One notable part of the fight was that Weepinbell managed to 2HKO Eusine's Haunter with Sludge Bomb, even though a 4x resistance! Haunter might be frail, but it just goes to show how strong having STAB Sludge Bomb is at this point of the game. Chuck's gym was absolutely free, i just mashed Sludge Bomb and only got hit once or twice through the entire thing. By the time i was done in Cianwood, Weepinbell was pretty overleveled compared to the rest of my team, so i didn't really use it as much until they caught up.
I decided to challenge Jasmine and Pryce out of order, considering the fact that Pryce's Pokemon are actually lower leveled than Jasmine's, i decided to challenge Pryce and his gym first. As previously mentioned, i didn't really use Weepinbell too much through this stage of the game because it started to get a bit overleveled compared to the rest of my team. However, if i were to theorycraft, i'd imagine that Weepinbell would be able to do ok against Pryce's gym as long as it could outspeed its opponents, it wouldn't appreciate taking any Ice-type moves, but Sludge Bomb is just so strong that it'd most likely 2HKO anything that doesn't resist it at worst. Against Jasmine, i'd imagine that Weepinbell would be able to do ok against her Magnemite, and could outspeed and put Steelix to sleep, although taking out the two Magnemite would take a while due to their resistance to Vine Whip and immunity to Sludge Bomb.
Just like against Pryce and Jasmine, i didn't really use Weepinbell very much against Team Rocket during the Radio Tower takeover due both to the matchups against the grunts and wanting to level up the rest of my team more (although as mentioned before, a lot of these matchups could be improved in theory if you use the Return TM on Weepinbell/Victreebel, especially considering the immunity to being poisoned the Bellsprout line has). However, it does well against any members of the Oddish family the members of Team Rocket have (including Ariana's Vileplume!) , as well as Silver's Meganium if you picked Totodile (it should do fine against Silver's Feraligatr if you picked Cyndaquil too, the same should apply to any earlier battles with him, it just kinda slipped my mind to mention it). By the time i defeated Archer, the rest of my team was up to par again in terms of levels, so i started using Weepinbell more again. From what i remember it did a pretty good job of clearing out Route 44 as well as Ice Path due to the strength of Sludge Bomb, and i used it pretty much exclusively on the way to Blackthorn. I know i could've gone to Ecruteak and caught Suicune at this point, but i wanted to have access to easy Ultra Balls beforehand, so i decided that going to Blackthorn first so i could buy them.
After reaching Blackthorn, i beat all the trainers on routes 45 and 46 and finally captured the final member of my team, a Skarmory. Once again, Weepinbell's Sleep Powder was extremely helpful for catching new Pokemon, although catching Skarmory was a pain regardless due to its low catch rate. After getting finished with that, i went ahead and challenged Clair's gym. I mainly used Feraligatr's Ice Punch to get through all the gym trainers and Clair's three Dragonair, but i used Weepinbell against her Kingdra. I had to use a Hyper Potion or two due to some bad luck with Smokescreen, but i was able to take out Clair's Kingdra with Weepinbell. Weepinbell's resistance to Surf and STAB Sludge Bomb really came in handy, despite Weepinbell's low defenses, it was still able to stomach Kingdra's Hyper Beam as well.
Once i finished defeating Clair and cleared the Dragon's Den, i went back to Ecruteak to catch Suicune. Weepinbell worked wonders with its resistance to BubbleBeam and access to Sleep Powder, and i was able to catch it relatively quickly. After catching Suicune, i went straight to New Bark Town and started making my way to the league. Weepinbell did well on the way to the league, and ended up learning Razor Leaf along the way. Right after learning Razor Leaf, i immediately used my Leaf Stone on it to evolve it into Victreebel. Now, just going to make a note here, if you didn't wait to evolve Weepinbell into Victreebel like i did and just evolved it straight away, i'd say that picking up the TM for SolarBeam on Route 27 is a good idea. The TMs for both Sunny Day and SolarBeam are available in Johto (if you don't have the Sunny Day TM, you can get it by returning to the Radio Tower after driving Team Rocket out of there and talking to a woman on 3F), and If you teach Victreebel both moves alongside Sludge Bomb, you should basically be set as far as moves go for the rest of your playthrough. Victreebel came in handy against Silver's Meganium (Feraligatr if you picked Cyndaquil, idk why you'd use both Bel and Chikorita on the same team), and it can also potentially do well against his Sneasel and Magneton in my opinion due to the lack of a solid STAB move from the former and its resistance to the latter's Electric-type moves.
Once i had leveled up all of my Pokemon to the low to mid 40s, i stocked up on items and challenged the Pokemon League. Below i'll list exactly what Victreebel did against all of the members of the Elite Four as well as Lance, overall, i'd say it pulled its weight throughout the league.
Will: Victreebel knocked out Will's Exeggutor and Slowbro pretty easily, i crit Slowbro with Razor Leaf and i'm not 100% sure if it's a OHKO otherwise. However, you can outspeed it and put it to sleep easily regardless.
Koga: Victreebel basically sat this one out. Just like against Team Rocket, i imagine it could be a bit more useful against him if you teach it Return, but even then, it's not going to do much against his Forretress.
Bruno: In a similar case to Chuck, Victreebel soloed Bruno on its own pretty easily.
Karen: Victreebel was able to take out Karen's Umbreon and Vileplume for me from what i remember, didn't bother using it against any of her other Pokemon although it could probably take out Murkrow too due to its lack of a Flying-type move and general frailty.
Lance: Victreebel started out the match by taking out Lance's Gyarados iirc, most of the rest of Lance's team was cleaned up by Feraligatr.
Alright, so onto Kanto. I'm going to compress everything in Kanto quite a bit compared to how i described Johto, considering all of the routes and route trainers should be easy to handle for your team as this point. The matchups against the gym leaders, gym trainers, Snorlax, Red, and arguably Cal (completely optional but he gives you a LOT of exp and money for beating him, i'd suggest fighting him as much as you can, especially when grinding for Red, he's stronger than pretty much every non Gym Leader trainer too, so having a good matchup against him is important if you want the extra goodies imo.) are what i'm going to mainly focus on.
Once i got off of the S.S aqua, i fought Lt. Surge pretty much immediately, Victreebel pretty much destroyed the entire gym by itself, Lt. Surge included, the only thing i'd really worry about is Electrode's Double Team, but it's really more of a slight annoyance than anything else. After defeating Lt. Surge, i headed up to Saffron City and challenged Sabrina. I didn't really bother using Victreebel against anyone in the gym, especially not Sabrina. If Victreebel was able to outspeed any of her Pokemon it could definitely do a lot of damage, but that wasn't a risk that i wanted to take. After beating Sabrina, i went north to Cerulean and solved the issues at the power plant as quickly as possible, interrupted Misty's date, and challenged her ASAP. As you might expect, most of the gym was a cakewalk for Victreebel, although her Starmie was slightly more annoying than expected due to its combination of speed, Confuse Ray, and Ice Beam. After beating Misty, i went through the Rock Tunnel to Lavender Town and picked up the EXPN Card so i could wake up Snorlax later, then headed west to Celadon City. Victreebel ran through the Celadon City gym on its own, i didn't really need to do anything except click Sludge Bomb to take out the entire gym honestly. After being defeated, Erika gives you the TM for Giga Drain, which is an option for Victreebel if you want it, personally, i didn't use it despite the increase in base power from Razor Leaf and the healing effect because i wanted to keep the PP that Razor Leaf has. Once Erika was defeated, i headed down Cycling Road to Fuschia City and challenged Janine's gym. Like the other Poison-type heavy areas of the game such as the Team Rocket arcs and Koga's battle, Victreebel didn't see a lot of action during this gym battle, although if you teach Victreebel Return, it should do fine against her, especially considering the relatively low levels of her Pokemon compared to the rest of the gym leaders in the region.
Afterwards, i traveled up to Silence Bridge and battled the Snorlax blocking Diglett's cave. Just like literally every other stationary Pokemon i've encountered so far, Victreebel was extremely useful against Snorlax simply because of Sleep Powder, which made it that much easier to catch. I traveled through Diglett's Cave to Pewter and challenged Brock. Victreebel absolutely ran through the Pewter City gym with no trouble at all, especially considering Brock's entire team has a 4x weakness to Razor Leaf. From there i traveled to Mt. Moon so i could challenge Silver yet another time. Just like the Victory Road battle, Victreebel is useful against Silver's Sneasel, starter (if you picked Totodile or Cyndaquil) and potentially Magneton. From there i battled all the trainers on the route to Cerulean, then backtracked back to Pewter and headed down to Viridian. While i was there i stopped briefly to challenge Cal in the Trainer House, just for the extra experience and money. Victreebel handled Cal's Feraligatr and Meganium handily, while Typh was basically Feraligatr fodder. Leaving Viridian City, i passed through Pallet Town and Cinnabar Island, talked to Blue, and challenged Blaine at the Seafoam Islands. Victreebel wasn't sent out against Blaine due to the fact that all i needed to do was click Surf 3 times to defeat him, although using Victreebel against him probably isn't an amazing idea regardless (although Sludge Bomb should still leave a dent). Once Blaine was defeated, i battled my way back up to Fuschia and went back to Viridian City to challenge Blue. Victreebel was able to take out Blue's Rhydon and Exeggutor quite easily, and can do alright against Gyarados too in theory.
After defeating Blue, i took the time to level up my Pokemon a bit by repeatedly rematching the Elite Four before battling Red. I got my team all the way up to the mid 50s/lower 60s and traveled through Mt. Silver to challenge Red. Despite being obviously underleveled, i was able to beat Red on the first try. Victreebel was able to take out Red's Pikachu pretty easily, and completely walled his Venusaur despite having an extreme level disadvantage against both.
Overall, Victreebel excelled in Kanto, it had a good matchup againt half of the gym leaders, made catching Snorlax way easier, and played an important role against both Red and Blue.