I'll speak about some that i finished the game with that havent been mentioned much or just a little:
Jolteon: Mid/high Tier
Early, Right when you get to Nimbasa
Jolteon being so fast you never have to worry about being outsped which goes great for last ditch efforts if you ever need to paralyze someone or just clean up after another poke. SpAtk is amazing, 110 does tons of damage. And the 95 base SpDef allows it to take strong special attacks which is nice. IIts ability allows it to take on every electric type and be an electric counter.
Kind of shallow. It starts off with thunderfang as its earliest STAB option, which isnt "that bad" early. Because there is not much difference between Atk and SpAtk split. Once it learns volt switch it's in business. Unfortunately Volt Switch isnt good in terms of leveling up. Once you reach Driftviel though jolteon gets a saving grace of signal beam from the move tutor. It learns Discharge around mid-game which makes it a deadly weapon. 30% chance of paralysis for team support. And then once you get shadowball jolteon is set for the rest of the game. Signal Beam, Volt Switch, Discharge, Shadowball. Great Coverage for the entire game. Even discharge is able to 2HKO Dreyden's Haxorus. Discharge/thunderwave is also great for catching pokemon including the three musketeers. If wanted to out of desperation then you can substitute discharge for thunder.
Making alot of the gym battles look free and providing great support to teammates for the E4. Aginst Elesa its kind of a stalemate of whoever does the most damage with coverage moves. Clay makes jolteon a benchwarmer. Skyla was so free that i fought her again to test my other pokemon out to make it a challenge. Aganist Drayden it surprising did really well. Being able to 2HKO haxorus was a real shocker(thats coming from a mild nature though). Marlon was the exact same way as skyla, so easy i wanted to fight him again. Against Corless it allowed jolteon to gain more life back, so that was pretty free as well. Vs. Iris it can save you from certain situations with paralyiss which goes a long way.
Being able to have 3/4 set done by midgame is really great. With only shadowball missing. It has great speed with paralysis support to help you in critical situations. Negative parts about it is that it has a horrible match up against ground types. So its always best to pair it with something that can take on ground types, thankfully there are not that many in-game. Discharge is a great move in single battles but in double battle its a huge double edge sword.
Skorupi/Drapion: Low Tier
Pretty good typing especially for the elite four. Having only ground weakness and the decrease in ground types late game really allow this pokemon to shine best when it evolves into drapion. Against the E4 it proved more useful then it did before them. However its 95 Atk always was never enough. If it hit with a super effective Atk then it was great but neutral damage was a huge let down. Speed was good, which only allowed him to outspeed most things with the exception of pokes that were meant to be fast.
This is also a let down. Without heartscales or if you want to grind through training to Lvl 49 with crunch, which is very difficult. dig/rockslide didnt do that much damage either. Since it comes late its not worth grinding so hard for it especially since you'll most have a full team already.
It was "fun" to play with, but it wasnt worth it. I played with Drapion purely out of fandom, but it was too much effor with little gain. The Attack power always left me needing more. Being able to shut down Shauntal and Caitlin was nice though, made those battles free.
Going to be also talking more in depth about Growlithe/Arcanine and getting vibrava late game instead of getting tranpinch early game.