Alakazam - I like their designs, using them in game, and I like some of their TCG cards.
Mewtwo - I like its design, using it in-game, and especially using it in the TCG.
Mew - I like its design and using it in the TCG.
Xatu - I like its design and using it in game. Also the HGSS TCG card looks really awesome.
Espeon - I like its design, using it in game, and pretty much all of its TCG cards for some reason or another.
Lugia - I like it for nostalgia reasons, its TCG cards, and its design.
Gardevior - I like the family's designs, their TCG cards, and using Gardevoir in game.
Metagross - I like the designs, using them in game, and their TCG cards.
Lati@s - I like them because of the movie they were in, their designs, and their TCG cards.
Jirachi - I like it because of its TCG cards and its movie.
Lake Trio - I like them because of their designs and their TCG cards.
Sigilyph - I pretty much just like this one because of its TCG cards.
Gothitelle - I pretty much just like this family because of a particular Gothitelle TCG card.
Reuniclus - I like using this family in game and their TCG cards.
Delphox - I like this one's design and using it in game.
And my other vote goes to Meloetta Aria Forme (because I can vote for Pirouette forme in the fighting type poll, right?). I like its design, the anime episodes it was in, its TCG cards, and its anime specials.