Quick opinions, anything Rhyhorn and below is niche despite the tier dividers but Rhyhorn/Meowth/Dratini are less niche than the Cs
S ranks:
Order doesn't matter to me, everyone knows why these are good, Staryu should be 100% use and Diglett/Egg should be like 95% but you can drop both occasionally to exploit certain tendencies
A ranks:
Voltorb is stupid as shit once Egg is worn down unless they also have a Pikachu, I don't know why people are so fast to boom it and move on.
Wag is stupid and should probably get banned for being uncompetitive even if it's checkable.
Pikachu is amazing, one of the best lategame cleaners once Egg is down, one of the only Voltorb checks, and Quick Attack does exactly enough to Diglett to put it in range of other Diglett, so even revenge killing it is dicey.
Gastly has Hypnosis and Explosion, which alone makes it viable, but it also walls a bunch of B and below stuff, is the only real option to catch booms, and Mega Drain can steal nice amounts of HP from Waters or just remove a Rhyhorn.
Slowpoke is really the only other Diglett/Psychic check besides Egg and it's a surprisingly great Poliwag check too thanks to Earthquake. Super underrated.
Abra/DZ are just Psychics and that automatically makes them solid here, nearly unresisted STAB with big upsides is great and they spread status.
B ranks:
Rattata is super underrated, I almost put it in A tier. It revenges or wins 1v1s from absurd ranges thanks to STAB QA, it's one of the few things that beats Diglett 1v1, Blizz coverage lets it goob Egg and Rhyhorn. It has all the tools it needs to be solid, walled by Gastly is really the only weakness it has.
Ponyta is overrated, getting OHKOed by Diglett is a huge downside, but people are also using it wrong - IMO the way to use it is to get it in free on Egg (revenge or a double) and then smack something on entry, set up Agility before getting the KO, then you can't be revenged by Diglett and get one more big hit off. Just taking a KO with it is really middling otherwise.
Doduo's decent, it has really bad weaknesses like getting obliterated by Staryu but it can do some good stuff by revenging a chipped Diglett and clicking Agility, but so can any Agility clicker really. I'm putting it here for now purely on how hard it hits and that it only has one wall, the severely overrated Rhyhorn, but it might be a C tier.
Rhyhorn is fucking ass. Genuinely this mon is so fucking bad and I want whatever people are smoking to put it at 5 or 6 or whatever. It only clings to relevance off of walling Voltorb, it's an exploitable momentum sink that gives up sleep for free and gets revenged by everything from full. How are we pretending a Pokemon that loses to literally everything I ranked above it except for Voltorb and Doduo is a top threat? Even Abra survives EQ 98% of the time, good lord. It beats Gastly too but only if Gastly doesn't have Mega Drain and doesn't hit it with a crit or special drop from Psychic as it comes in, and even then, taking literally any stray hit means Diglett now revenge kills it too. This should honestly be the start of my C tier but I'm giving it some grace.
Meowth sucks, only up here for 90 speed.
Dratini was by far the most misused mon all tournament, why the fuck didn't anyone click Agility? Why did people just click Blizzard in front of Diglett instead of getting your Agility so you can take 1.5 KOes? Travesty. It's not terrible, may honestly be better than Doduo and I should put it above Rhyhorn and Meowth but I'm being conservative.
C ranks:
Horsea has Agility so it's usable, only having Water/Ice coverage is shit though.
Pidgey is genuinely trash, Rattata is just better and I don't think having a one-time EQ switch-in is worth that much, but it still has some niche.
Venonat is honestly a very cool mon, 2HKOes Egg, Psychic is a pain in the ass to switch into as is Stun Spore, and it's a faster sleeper than Egg without an Ice weakness. Unfortunately gets goobed by Psychics and Ponyta and has no useful resists but building a nat lead team that completely destroyed Cake's lead Voltorb stuff was a highlight of the tour for me, even if I wasn't the one piloting it.
Bulbasaur has some tricks with that Electric resist but lack of Stun Spore hurts; Razor Leaf might be cool combined with some para spreading and you can definitely use it as an Orb/Pika check to get sleep while preserving Egg. I could see it moving up maybe but walled by Gastly + Ice/Psy weak + no Ground resistance + no Stun Spore is rough.
Eevee is bulkier Rattata but no coverage and the bulk only matters in a couple niche spots; I think Blizzard even off Rat's nonexistent Special is better than anything Eevee brings, but it has some potential.
Cubone's one of the only things that tanks a Diglett EQ on switch and it role compresses Voltorb check/Diglett check/good coverage all into one package, but it's mediocre at the latter two roles so it's down here.
Magnemite hits like a truck but needs Egg chipped by like 40% and Diglett gone, Voltorb does it better for most use cases.
Omanyte/Kabuto are both ass but they have a tiny niche in walling stuff like Doduo and Eevee and Pidgey while being faster than Rhyhorn and outspeeding/tying Egg (and not getting oneshotted as freely), but being Elec weak instead of immune is ass.
Clefairy does not have bulk and anyone putting this in B or higher has either not used it or somehow failed to notice their Clef getting 2HKOed by everything. It's worse Drowzee except versus Diglett and (slightly) Rhyhorn thanks to Blizzard.
Shellder's ass, again the bulk doesn't hold up down here but it has Explosion, a couple useful resistances, and it usually survives 2 Diglett EQs, but 34% to get KOed before crits is still really really bad.