Civilians

Pichu -> Pikachu -> Raichu
Electric
Static: Pikachu will paralyze his target each Night, making him or her unable to vote the next Day or use a Night action the next Night.
Lightning Rod: Raichu can target two individuals and draw their powers to himself, negating them.

Bulbasaur -> Ivysaur -> Venusaur
Grass / Poison
Overgrow: Ivysaur’s vote is worth two.
Chlorophyll: Venusaur’s begins with -2 votes.

Charmander -> Charmilion -> Charizard
Fire
Blaze: Charmilion can light up the Night, discovering who one person targeted and picked for evolution.
Solar Power: Charizard can skip one Night phase, causing two consecutive Day phases.

Squirtle -> Wartortle -> Blastoise
Water
Torrent: Blastoise will wash one vote away from his target the next Day.
Rain Dish: Blastoise will cause it to rain, washing away all votes from his target the next Day.

Pidgey -> Pidgeotto -> Pidgeot
Normal / Flying
Keen Eye: Once, Pidgeotto will select a civilian Pokemon and learn what that Pokemon’s current ability is.
Tangled Feet: If Pidgeot is confused, he cannot be killed.

Eevee -> ??? -> ???
Normal
Has multiple potential evolvements. *Secrets*
As soon as someone votes to evolve Eevee, Eevee will tap into that first voter's Pokemon type, which will determine how Eevee evolves: If water, Vaporeon. If electric, Jolteon. If fire, Flareon. If psychic, Espeon. If grass, Leafeon. If ice, Glaceon. If fairy, Sylveon. If dark, Umbreon.
Water Absorb: If a water type picks Vaporeon to receive an evolution point, he will be off the next Day’s poll.
Volt Absorb: If Jolteon votes for an electric type to receive an evolution point, he will be protected from the kill that same Night.
Flash Fire: If a fire type chooses Flareon to receive an evolution point, he lights up the Night, learning who picked him.
Magic Bounce: Espeon can change someone else’s target.
Leaf Guard: During the next Day, anyone who votes for Leafeon cannot target him that Night.
Snow Cloak: Glaceon brings hail, disrupting her target’s BTSC the next Day.
Pixilate: Sylveon affects her target’s vote the next Day. If her target is a civilian, the vote is worth 2. If her target is mafia, the vote is worth -1. If her target is independent, the vote is worth 0. Her target will be unaware of this change.
Inner Focus: Umbreon can learn if anyone targeted him each Night.

Snover -> Abomasnow -> Mega Abomasnow
Grass / Ice
Snow Warning: Abomasnow summons a hailstorm, eliminating her target's BTSC privileges for the next Day.
Soundproof: Once, Mega Abomasnow eliminates all BTSC for the next Day.

Froakie -> Frogadier -> Greninja
Water / Dark
Protean: The next time Frogadier votes for someone in the lynch poll, he will temporarily change into one of the types of the individual for whom he voted.
Water Shuriken: Once, Greninja can switch the lynch.

Gible -> Gabite -> Garchomp
Dragon / Ground
Sand Veil: On one occasion, Gabite can protect himself from all negative actions.
Rough Skin: Anyone who targets Garchomp will begin the next Day with one vote against him or her.

Ralts -> Kirlia -> Gardevoir
Psychic / Fairy
Trace: Kirlia can target someone during the Day, and use his or her ability that Night.
Telepathy: If a civilian Pokemon targets Gardevoir with a negative ability, it will fail.

Torchic -> Combusken -> Blaziken
Fire / Fighting
Blaze: Combusken can light up the Night, discovering who one person targeted and picked for evolution.
Speed Boost: Blaziken can use Blaze twice each Night.

Igglybuff -> Jigglypuff -> Wigglytuff
Normal / Fairy
Sleep: Jigglypuff sings, making her target drowsy. The drowsy target will fall asleep and sleep through the entire next Day, unable to post or vote.
Cute Charm: Wigglytuff can sing too, but will charm her sleeping target into staying silent while voting for her preferred choice.

Munchlax -> Snorlax
Normal
Immunity: If Snorlax is put to sleep, he cannot be killed.

Riolu -> Lucario
Fighting / Steel
Steadfast: Lucario uses his fighting skills and determination to protect his target each Night.

Mew
Psychic
Does not evolve. *Secrets*
Synchronize: Anything Mew is targeted with will be redirected to his target (unless he targets Mewtwo, then the targets against Mew simply fail). If Mew targets Mewtwo, Mew joins Mewtwo in BTSC, and shares Mewtwo’s win condition.
Mafia
Knocks Out someone each Night
Has BTSC

Meowth -> Persian
Normal
Limber: Persian will be immune to paralysis.

Inkay -> Malamar
Dark / Psychic
Contrary: Malamar negates his target’s Night action.

Gastly -> Haunter -> Gengar
Ghost / Poison
Levitate: Haunter will be immune to the first lynch against him.
Cursed Body: Anyone who targets Gengar with a night action will target himself instead.
Independent

Mewtwo
Psychic
Mewtwo wants to build a superior army of Pokemon clones.
Mewtwo wins by lynching any three fully evolved Pokemon and being alive when this is achieved. Lynching Eevee or Mew will not count toward your win condition.
Pressure: You may select two individuals instead of one to evolve each phase.
Unnerve: If anyone targets you will a kill, it will be neutralized, and the one targeting you will begin the next Day with one vote.