Here's the next batch from me. I'm actually getting close to finishing up all the runs I intend to do. I can say now that I will be using Tauros for the next run that I do. Given how much I've been shitting on it in this thread, I guess it's time!
The following is for Gold and Silver as usual.
Chinchou
This is glorious. Chinchou is yet another great mid-game Water that benefits from convenient location and catch level, well-rounded stats and immediate access to a powerful STAB.
The main thing it has to distinguish itself from other Waters is its Electric-type and Spark. These attributes make Chinchou one of the best Waters for dealing with other Waters and that's useful considering the Water routes leading to Cianwood are coming up for it. In addition, Water/Electric is a fantastic attacking combo for when it comes - Chinchou has great match-ups against Chuck, Jasmine and Pryce, and it's also able to do more damage to Clair's Kingdra that a lot of the other Waters can do.
On the flip side, Chinchou doesn't get any Ice moves in Gold/Silver - not even Icy Wind. This makes Chinchou less effective against Grass-types and the Dratini line than the Ice Punching Waters. I personally prefer the Electric STAB since I think Grass is pretty easy to cover elsewhere on a team, but it does mean that Chinchou will need a bit of help at times. Vileplume is used by 2 compulsory trainers and there is a Grass gym leader for you to beat after becoming champ, so Chinchou would prefer Fearow or something to deal with those.
Chinchou is also in the Slow experience group and needs to grind to level 25 for Spark so it doesn't have the Water-slaying power on its side right away, although i didn't find this to be a huge speed bump. I suppose Chinchou could try Rain Dance/Thunder as well but Spark is good enough.
Overall, I think Chinchou is the best of the mid-game Good Rod Waters in Gold/Silver and is right up there with Lapras in viability for efficient runs.
Doduo
Unfortunately, this thing's late appearance dooms it to the lower tiers, but it still has situational usefulness for some runs. Flying STAB is very useful for the Elite 4 and beyond, and Doduo learns Drill Peck at level 33 (as long as evolution is delayed), so if you somehow find yourself lacking this sort of coverage at this point in the game, Doduo might be the Pokemon for you. Tri Attack is also neat since Return won't be very powerful when it's first caught. It isn't too difficult to grind it against the Grass-types on Route 44 either.
However, much like Ponyta, Doduo is also competing with other Pokemon for a team slot that provide the same coverage: Lugia and Ho-oh. Lugia's Aeroblast does more than Dodrio's Drill Peck due to the power advantage, and Ho-oh is just way stronger (albeit while relying on Fly), and they have so many other perks over Doduo that it ends up being difficult to justify using it even in the above situation. That's before you bring up Pidgey and Spearow existing.
Comparisons aside, Doduo will fall somewhere in the D/E tier range depending on how much you want to weigh its availability against it. I factor availability quite heavily myself but it's effective during the brief time it's on your team.
Krabby
This Water appears quite unique in terms of stat distribution, although it's actually built similarly to Gyarados: both have high Atk, decent Speed when evolved, and terrible Sp. Atk, with the defensive distribution being the main point of difference. Krabby therefore doesn't place a lot of important on its Water STAB as other Waters do, although STAB Surf is still useful at times.
There are a few ways to obtain Krabby. For this run, I went with the Old Rod method. This is the earliest time that Krabby can be obtained, although it requires a longish back-track from the entrance of Union Cave to Cherrygrove City. At that point it's at level 10 and only has Bubble, but since Bubble destroys Geodude and Onix regardless, it doesn't take much effort to get it to level 12 for ViceGrip. ViceGrip in particular helps make up for its lake of Headbutt and Swift to an extent.
It is probably worth noting here that Krabby has 105 Atk, which is equal to that of Feraligatr and impressive for an unevolved Pokemon. Despite this, I was underwhelmed by it. I guess at that early point of the game, differences in stats really don't mean a great deal, so it wasn't exactly rampaging through things any better than a starter spamming Headbutt. I also found it to be a bit slow at times, but maybe I expected too much of 50 Speed. In any case, Krabby doesn't do anything essential during the early parts of the game, so it might be better to wait for the Good Rod to obtain it. That method doesn't require a back-track and it'll be able to learn Strength and Surf immediately, which is its main form of offense. It really doesn't get much outside of those (it gets Dig as an egg move but isn't compatible with the TM). Perhaps I should mention that it gets Guillotine at level 27, earlier than any other Pokemon in the game with OHKO move access, but I explained my lack of interest in that move when I did Pinsir and I'm not not getting excited over it now.
I did find Kingler to be pretty effective. 130 Atk and 75 Speed is nothing to scoff at, and it can work wonders on routes and the like just by spamming Strength on things. That's really all it does though. The lose of 100% critting Crabhammer as a STAB option was a significant nerf compared to gen 1.
Comparing Krabby to other Waters is difficult. I personally view Krabby in a similar way to Heracross and Pinsir in terms of function, in that it is more like a Normal-type without the STAB boost than a typical Water-type. But I don't think it holds a candle to Chinchou/Lapras/Tentacruel/etc. Krabby belongs further down the viability list near the likes of Goldeen and Horsea.
Machop (with trade)
Machop is obtainable as an in-game trade in Goldenrod City, and it seems designed to be the ultimate Miltank counter. It's basically the only thing with Fighting moves at that point in the game, it resists Rollout, it has a Gold Berry attached to recover from some Stomp damage, and it even comes as a female which means that Attract is ineffective against it. However, Machop's effectiveness in that match-up will depend on how much Miltank spams Stomp since it has the Speed advantage, and Machop is prone to flinching and isn't exceptionally bulky even with the Gold Berry. In this run, Miltank used Rollout which lead to Machop just sweeping her team - there aren't many Pokemon that can claim to do that.
Machop is useful beyond that because Fighting is a solid offensive typing that is also quite rare. There aren't a lot of Fighting-types worth using in GS. Mankey is probably the only other one that's worth the time (I don't really count Heracross as "Fighting" due to its reliance on Normal moves, and Poliwrth is post-champion in GS and functions more like a Water-type anyway). Machop also has boosted experience (and isn't difficult to obtain since Drowzee is readily available), high Attack and bulk, and decent coverage options like Dig/Earthquake, and even the elemental punches (Machamp's 65 Sp. Atk is just good enough to use these for selected route targets imo).
Machop has a few issues. The main one is limited options for STAB. Machop has a neat signature move in Vital Throw which is the strongest accurate Fighting move in GSC (don't say Reversal haha), but it has negative priority, which won't matter in some match-ups due to its low Speed but does cause it to eat extra hits on routes. Machop's strategy will probably involve having both Vital Throw and Karate Chop, with the latter being used for routes quite often, but if it can't OHKO with Karate Chop then it's taking a hit no matter what it uses (Karate Chop is often better to use against faster stuff anyway since 2 Karate Chops do more damage than 1 Vital Throw with the result still being Machop taking a hit, plus Karate Chop has a high crit rate). Machop also evolves a bit later than would be ideal, and as mentioned above, it's Speed is lacking.
I chose to evolve Machoke for this run. I haven't tried Machoke yet but just from observing Machamp taking hits, etc., I suspect the stat difference (including a massive 30 point difference in Atk) might be important. The difference between trade/no trade is obviously not going to matter as much as with Haunter, but it seems more important than with Graveler and Kadabra, so I'm inclined to say that a tier difference between trade and no trade is justified in this case.
Either way, I agree with Machop's current placement in B-tier assuming it can be fully evolved by the player. I think a lot of that comes down to the Whitney match-up, but it has several good match-ups after that too and packs quite a punch with 130 Atk.
Meowth
Another Mid-game Normal. This one is less powerful than the others, but that's more of a reflection of how good those are rather than of Meowth being bad. Meowth is still decent on its own terms. It's a little weak before evolving, roughly in the same tier as Jigglypuff in term of raw power, albeit with way better Speed. I just threw Headbutt on it and it did OK on routes. It wishes it could evolve earlier given the middling attacking stats, but once it does it is basically like Aipom/Raticate/Furret but with amazing Speed.
Meowth's move pool falls somewhere between Tauros and Furret in terms of size and quality. Meowth somehow lacks Dig, but it at least gets Shadow Ball and Bite/Faint Attack for the occasional Ghost. The fact that it is a Normal-type with Bite is kind of nice because it allows it to do well against Morty's gym (and unlike Snubbull it has an actual Speed stat). Thunder and Icy Wind can be added to make it some bizarre mixed attacker. Pay Day can also be used to get some extra cash but the gains are minimal and not worth the use of such a weak move outside of finishing stuff that survived Headbutt/Return off.
I can't think of much else to say about it. It's a fairly generic Normal-type, perhaps a Normal-type equivalent to Goldeen or something. It's hard to justify its use over other Normals, but it does fine with what it has and should be C-tier minimum in my opinion.
Oddish
For all intents and purposes, Oddish is identical in Bellsprout in terms of the role it plays, except it's even worse since it comes at a less useful time (missing out on those Water- and Rock-types on Route 32 and in Union Cave that Bellsprout is able to assist Quilava in removing) and has less power, epsecially with only having Absorb for Grass STAB for quite a while. Having said that, Oddish can still be of use for Cyndaquil users since it can beat Croconaw/Feraligatr and helps with the Water routes and the occasional Geodude/Graveler/Onix. It also gets Petal Dance eventually, although it won't see much use outside of Kanto. Much like Bellsprout, Oddish has a convenient grinding opportunity, in this case in Union Cave against the Geodude and Onix. I did this run in Silver; Gold offers even better grinding because of Sandshrew's presence.
It is worth noting that Oddish has the opportunity to evolve in Johto with the Sun Stone, which most other Stone evolvers can't boast in Gold/Silver. However, I actually question whether this is the best way to use Oddish. Bellossom's Sp. Atk and Speed are only marginally improved over Gloom's, and the Atk boost is offset by the STAB boost Gloom receives for Sludge Bomb (which can only be learned as a Gloom anyway - Bellossom isn't compatible with the TM while Gloom is), so ultimately all you get is some more bulk and a miniscule boost to its Grass moves, at the expense of a stronger Sludge Bomb which is its strongest move when it arrives and remains that way for the rest of Johto. I therefore chose to leave Gloom unevolved for this run. I'm not entirely convinced that Bellossom deserves to be a tier above Vileplume for this reason.
Oddish is probably the third best Grass-type after Bellsprout/Chikorita, but that's more of a reflection of how mediocre the Grass-types are in this game rather than of Oddish being particularly good. As mentioned above, Oddish can be useful for Cyndaquil users due to its type synergy but even then it is burdened with low Speed and asucky move pool, with many underwhelming match-ups.
Onix (no trade)
I just used this for completeness since I've done Steelix already. All I'll say is that I'm still convinced that Onix's tier placement should not be impacted by the players ability to evolve it. Separate entries for both options are fine I guess, but they should be in the same tier since it is unreasonable to assume that it will evolve before the S.S. Anne, and at that point Onix is still going to be doing plenty in Kanto (some match-ups are worse than Steelix but it's better against Blaine/Blue's Arcanine/Red's Charizard and just as good as Steelix in some other match-ups).
Sunkern
This was less bad than I was expecting, but still pretty bad. It offers the same thing that most Grass-types do, which is little. Sunflora's main niche among the Grass-types is the Sp. Atk of 105, which is only second to Exeggutor (which isn't going to happen for you in Gold/Silver) and is well above the unevolved Grass alternatives at that point. It also isn't all that hard to grind up as Sunflora - it's in the Medium Slow group and gets plenty of HP from Drowzee.
It is sadly stuck with Mega Drain for a while. Annoyingly, Sunflora does have Razor Leaf in its move pool, but it only learns it by evolving at level 10 or below. Since the Sunkern in National Park seem to be at level 11 minimum, Razor Leaf is unobtainable unless you go to the trouble of breeding a new Sunkern, which I obviously do not recommend. But Mega Drain still does decent damage when compared to, say, Quilava's Ember. It gets Petal Dance at level 31 too, and that exacerbates the power difference between itself and the Grass-types even more for a while. The rest of its move pool is similar to other Grass-types: Sludge Bomb and Normal moves. Sunflora's 75 Atk isn't terrible but the lack of STAB on Sludge Bomb makes it less useful here than for Weepinbell and Gloom.
Some other flaws warrant mentioning. Firstly, its Speed is pretty bad. Level advantage helps sometimes but it does get outsped often. Sunflora's special bulk is at least decent, although its physical bulk is not, so the Speed matters sometimes. Another problem with Sunflora is that you'll want to evolve it right away, and that requires winning the Bug-Catching Contest first. I was able to win it fairly quickly for this run but there is a lot of RNG involved with the scoring system, so much so that simply catching a full HP Scyther isn't necessarily a guaranteed win. I can definitely see an unlucky player being stuck here for longer than would be considered reasonable.
I wouldn't recommend Sunkern to someone doing an "efficient" run, but I do think that compared to other Grass-types, it has its advantages and disadvantages. Again, people who chose Cyndaquil will find some use for Grass-types, and Sunkern is no exception. While it is clearly less viable that Bellsprout for this purpose, I honestly don't view Sunkern as being any worse than Oddish overall.
Zubat
This has been discuss in this thread a lot already and I don't have much to add that hasn't been said already.
I chose to use Zubat from the beginning rather than wait. I can confirm that it's pretty bad initially. Leech Life as its only damage attack is pathetic not just because of the low power but also because of the PP. The fact that Zubat walls Bellsprout is helpful but the low PP of Leech Life is an unavoidable obstacle. Thankfully, Zubat learns Bite at level 12 and is compatible with the Swift TM, but even then it's kind of underpowered in comparison to an average early route Normal or the starters.
So yes, perhaps it's wiser to skip all of that and catch a wild Golbat once Surf is usable outside of battle, perhaps utilising a Friend Ball or X Item spam to increase its happiness quickly. Crobat itself is not too bad thanks to its amazing Speed and decent stats overall, but I actually found it to be identical in function to Scyther in that it's focused on Normal moves initially but eventually gets Wing Attack (it doesn't get Sludge Bomb or Shadow Ball in this gen), except that obtaining Crobat in the first place is more convoluted.
I would just leave this where it is on the tier list. It doesn't deserve to be higher than C-tier in my opinion.
