First Playthrough:
Gardevoir~
Back in the day, Ralts was in the little shack where you had to pay the bum money to gain access to. Once you evolved it into Gardevoir, It completely destroyed everything
Dragon mono:
Goodra~
Goodra was amazing once it evolved in my Dragon mono and it just annihilated everything in it's path and looked adorable at the same time~
Steel Mono:
Empoleon~
Sooooo bulky when it evolved and it helped in a lot of gym battles. Also my fav starter <3
Second Playthrough:
Gyarados~
OMG PLZ NERF