Ok, let's go.
I want to break down each era prior to going into each mon individually.
Medieval
For Medieval, I have mixed thoughts. Medieval was set up o be a very offensive playstyle, with essentially having a team of 6 wallbreakers. Most of them have defensive utility but they aren't realy defensive Pokémon. So I was expecting teammates that further drove home the offensive nature of the type, since it is notably slow for being mainly offensive, and was pretty physically leaning so addressing those issues seemed to be paramount. So it was pretty surprising, and honestly disappointing to see that subs more or less defaulted to more slow wallbreakers or fat walls. Was pretty lookng forward to a playstyle that leaned heavy on all out offense similar to Fighting in Mono, so to kinda sorta default to tryjng to be typical Bulky Offense / Balance type beat was blegh to me. Well, it is what it is.
My sub. He cool. I basically modelled him off the expectations I listed off, so it embodies that, giving the type a fast special attacker. Not much else to say its my sub I think it's good.
I literally do not understand how this won, I will not lie. At face value it seemed really weak as a Pokemon, clocking a mediocre statline without much of an impressive set of tools to compensate for it. I think the mere presence of Rain may be it's only saving grace as a warranted addition to a team, since the team only had a single viable special attacker prior and Water Shuriken under Rain at +2 might be pretty good. But you couldn't knw that woukd happen when voting for it, so it being second highest is crazy to me ngl.
I like it, its a defensive Pokémon that gives its Era hazard control while still not being a passive mess. As I said, I don't like how mons like these essentially force the type to play differently than what it initially gamed for, but how it plays as a mon at the very least doesn't feel like like a slap in the face of momentum due to Drizzle Scalds.
Pretty indifferent to the mon. Its a slow wallbreaker on a type that really didnt need another slow wallbreaker. Its a special attacker, that's good, gives the type that. Also has a good matchup versus Conkeldurr on Present Day if you opt for physdef. Outside of that, and it's Electric immunity, not sure what elsw it adds to the Era on a whole.
The most powerful addition to the metagame, being a terrifying wallbreaker thanks to Sheer Force boosting its coverage moves to near STAB Power, and in general having a pretty hard to switch in Draco Meteor, makes Tarranite a devastating tool for Medieval. Extreme Speed also makes it pretty hard to revenge kill lol. I would not be shocked if it may ultimately need a nerf.
Least favorite addition. Pretty much a fat passive wall that on paper makes no sense to add to what was preconceived about Medieval, and its recent additions only add to it's sorrows. I can't see myself running this over Torkappa on any given team, as I don't think the extra options it's Fairy type adds have too much merit on the squad (tier lacks Dragon variety, team has multiple Fighting resists and Dark ones too.) I think it's best bet is to load into a mirror matchup that lacks Torkappa.
Present Day
Present Day imo was already pretty strong right off the bat and had options to go into pretty much any avenue it wanted. I think the additions made captured the spirit of what the Era was established well, and outside of a few outliers lived up to the team's expectations imo. I will say though, that the Eramons are for the most part alot weaker than their normal counterparts, so that might feel a bit awkward in teambuilding/gameplay.
Not much else to say, it's Gliscor that's part Fire instead of part Flying. Fire Ground is an excellent offensive typing, and is decent at defensive capacities. Adding a pretty solid Fire resist to the tier that can block Volt Switch is cool but the best VSwitch user brick walls you and 1Shots :(. Also not a fan of it losing Spikes, its basically the only way it's team coud get them off.
Great wallbreaker, I believe with the highest attacking stat in the game so far. It can pull off a large variety of roles for it's team from Specs, Scarf, CM and even a chance at some utility esq options. Not much else to add it's my mon, I will say it loves and hates the existence of Glisipirin.
Poor Heradoze. Imo a decent Pokémon that has the very unfortunate task of being on a monotype adjacent team with Conkeldurr. There is like no reason to run this over Conkeldurr. Conkel is bulkier, hits harder and has STAB priority to circumvent the pitiful +5 speed advantage that barely mattered anyway. Heradoze doesn't have a spectacular matchup versus te Electric tpes in the meta either if we are being honest, with most having SE secondary STAB or can hit hard enough to kill it after minimal chip. Its just too hard to justify running imo, if you can argue otherwise I'm ears.
God awful. It won because of a silly pun that works really well for it's era - thats it. It's more or less worse Comfey. How do you make worse Comfey? The mon didn't even have an actual role description becauyse it accomplishes next to nothing. Defog is the only mentioned trait and I kid you not, I'd rather run Conkeldurr, Cinderace or Tinted Lens bird as hazard control. Lowkey pissed people would even vote for this, and completely flabbergasted that the creator thought this was a good idea.
This not getting Moonblast genuinely drops it several octaves down in viability for me. Idk why people are denying their subs good STAB moves. Anyway, Sacrf sets are tge ultimate revenge killers, but the speed of the tier as a whole and it's relatively modest damage output will most likely force it into Choice Specs, where I see it performing well, as it can comfortably run Modest. As I said, no Moonblast REALLY cuts into its power versus neutral targets but it's still a pretty solid special attacker for Present Day teams.
Matchup Fish incarnate. Essentially sidegrade Mimikyu, trading better speed, better offensive movepool and raw bulk for worse every thing else. Jury's out on whether or not that's a fair trade, and I think this thing lives or dies on what you actually face on preview. Early Civ gets curb stomped basically on turn 1, Far Future has warm time but can pull off good wins, Medieval should beat this unless you play sloppily and Present Day, its own Era, basically makes it dead weight. In a tier thats already matchup based, not sure if it is gonna be worth the addition long term, but we will see how other eras develop in response to it.
Was gonna let this one slide, but ultimately I think letting this one in would set a bad precedent for allowing overly memey submissions, so sadly veto'd. Crossover Chaos has you covered if you wanna play as Mario in Gen 9, at least.
These three had no era attached, so we're just going to assume Present Day and call it a day.
Minor thing, Heatran has two abilities, not just one. Veto'd, but just make Drought either the main abil or HA, and adjust the other accordingly.
PQRDG
lavarina
LOrd Fernando
Gaboswampert
Orangesodapop (SV)
Beebos
flareth13
Wyviper (Gaboswampert)
for losing its only physical STAB due to Gear Grind being dexit'd at the time of writing and being the most passive spinner ever running BPress/RSpin/VSwitch/Recover. No, it doesn't even get Iron Head. Friendly reminder that returning mons importing their movepool from before Gen 9 lose any moves that were dexit'd!
Industrial Revolution and 
Apocalypse eras! To help further elaborate on each and give some relevant themes...
