Ok this is gonna be an essay guys, all gens here ya go:
Kanto:
- Gengar: the entire design is just so loveable, funny and cool imo. A little stout ghost that is grinning all the time, and making fun of evrything, it almost reminds me of myself, since i used to not take anything seriously as well :] Also, the creepyness i later learned about, namely him being the shadow of a clefairy, and that it cools everything, just made me love gengar more, prolly on my top 3 favorite pokes.
- Arcanine: I guess this is largely because i never liked charizard in the first place, but also, i fell in love with its sprite in FierRed, and training the little Growlithe all the way till Sevii SIlands where it turned into this giant majestic dog.
- Pikachu: being hipster is 2 mainstream.
- Dragonite: ever heard of being an adorable badass? thats what he is, but lance, i fell in love with it when lance raped me with 3 of this guys, later on id go and rape him for a. revenge b. he totally hacked
Johto (from here on it gets long):
- Scizor: i love red (i guess thats why Red is my favorite dex holder, tho, whose isnt?) and scizor's battle pose and design seemed appealing af to me cuz of how he had METAL PINCERS. #btchesluvmetalpincers
- Typhlosion: its whole evolutionary line is top-notch design, yet so simple, starting from the little cyndaquil all the way to a giant enraged...idk what it is rofl, that hasd a ring of fire in his neck. Holy. Crap.
- Kingdra: simple design, and just all it needs to be appealing imo, an underwater dragon that is an arrogant ashole is kawau desu cool.
- Ho-Oh: i have no explanation for this one, he just is in my favorites because of similar reasons to arcanine, he's majestic, he's big, and he's pretty damn colorful too.
Hoenn:
- Blaziken: Chuck Norris got turned into pokemon here imo. Also, Mayand Sapphire's representative pokemon so that automatically makes it cool.
- Sceptile: here the anime plays more of a role, im pretty sure im not the only one who needed a sceptile when they saw ash's trecko's badassery.
- Salamence: pseudo legendaries have always been my thing, this guy deserves a spot because he (along with chomp) were my first ones, when i didnt even know what it meant. Also, the dex entry of how bagon achieved his dream of flying was appealing to me.
- Latias: she's just cute, and adorable, i h8 her in the anime since she blatantly goes against Advanceshipping tho.
Sinnoh:
- Empoleon: my first starter to ever reach level 100 and he is a ***** penguin, i love penguins, i also love the word emperor, which i always realted with him.
- Gallade: justice bringer all the way, the blades it has seems liek he can go through anything like who gives a ****, and the contrast between him and kirlia is cool as well.
- Lucario: training my riolu since it was just an egg played a huge role on this one, but also the fact that he controls aura, supposedly life energy = 2mchepicness.
- Gible/archomp: all time favorite pokes by a longshot, the former is simply adorable and the latter raped the crap out of the 8th gym, elite four, and victory road in Platnum, terrific design, just fitting to the violent nature dragons are supposed to have, and Cynthia gives him even more points.
- Darkrai: read pikachu
- Dialga; cuz diamonds are cool as that, he raped the shit outta palkia in the movie, and he **** controls time.
Unova:
- Volcarona: flame moths all the way, can you believe i actually trained this thing in BW1 starting from the egg? I regret nothing.
- Hydreigon: #3heads
- Keldeo: here competitive scene comes into play, because i was one of the first ones to actually use keldeo succesfully. Also, he's a pony, im a brony, nuf said.
EDIT; forgot to mention Shaymin and Skymin, the former for being absolutely adorable, not to mention likeable in the movie, and the latter for being badass, not to mention the entire theme around its abilites are really cool.