These are mine.
Note: I'm not repeating Pokemon, so once one's mentioned, it won't appear in the list again.
Bug: Venonat, Beedrill, and Volbeat
Why: Venonat because it's cute. Beedrill for nostalgic reasons (and because the one I have in Fire Red is awesome for in-game battling). Volbeat because it's awesome in-game too.
Dark: Umbreon
Why: Nostalgic reasons. My Umbreon in Crystal was awesome.
Dragon: Flygon
Why: Mostly the design, admittedly.
Electric: Raichu and Electabuzz
Why: Both nostalgic reasons and because I've always found it cute. It was my original favorite Pokemon and thus served on all of my teams back in my RBY days. Electabuzz, meanwhile, is there for in-game reasons. I've got one on my Fire Red team that's known to kick tail and wipe the floor with the Elite Four.
Fighting: Medicham
Why: Because, thanks to Sapphire, I've found that this Pokemon literally kicks tail.
Fire: Growlithe
Why: Because of "Holy Matrimony!" Enough said.
Flying: Farfetch'd and Crobat
Why: I've always loved how quirky Farfetch'd is, and a Farfetch'd used to be my best Pokemon on my RBY teams (back before I learned the power of EVERY OTHER FLYING POKEMON). Crobat, meanwhile, serves on my Sapphire team as one of my four strongest Pokemon. It seriously kicks tail before my opponents even realize it.
Ghost: Haunter
Why: I blame this completely on the anime.
Grass: Cradily
Why: Because it's quirky and one of the best contest Pokemon I have in Sapphire.
Ground: Marowak
Why: General usefulness in-game. I've got one in Fire Red that's awesome.
Ice: Cloyster and Jynx
Why: Both for nostalgic reasons. I have one of each on some of my ASB teams that have been known to rock opponents.
Normal: Rattata and Kecleon
Why: Rattata because it's cute (and because of Hyper Fang) and Kecleon because of ASB-related reasons.
Poison: Arbok
Why: In-game purposes.
Psychic: Gardevoir
Why: My all-time favorite Pokemon for the moment. Its design is elegant, its stats and movepool make it a nice in-game Pokemon, and the one I have in Sapphire seriously kicks tail.
Rock: Sudowoodo
Why: Because it's just as quirky as Farfetch'd.
Steel: Scizor
Why: I also blame this solely on the anime.
Water: Squirtle, Lanturn, and Starmie
Why: Squirtle because of Ash's Squirtle. Lanturn because it's one of my best on my Sapphire team. Starmie because of ASB-related reasons.
