From Bulbapedia, the community-driven Pokémon encyclopedia.

The following is a list of Character's Pokemon that can go by different names

More to be added...

Anime

Ash's Pokemon

	Pokémon	Alternate Names
	Ash's Pikachu	N/A
→ → File:Ash's Butterfree.png	Ash's Butterfree	Ash's Caterpie Ash's Metapod
→	Ash's Pidgeot	Ash's Pidgeotto
	Ash's Bulbasaur	N/A
→ →	Ash's Charizard	Ash's Charmander Ash's Charmeleon Damian's Charmander
File:Ash's Squirtle2.png	Ash's Squirtle	N/A
→	Ash's Kingler	Ash's Krabby
	Ash's Primeape	Anthony's Primeape
	Ash's Muk	N/A
	Ash's Tauros	Brock's Tauros
	Ash's Lapras	N/A
	Ash's Snorlax	N/A
	Ash's Heracross	N/A
→	Ash's Bayleef	Ash's Chikorita
	Ash's Cyndaquil	N/A
	Ash's Totodile	N/A
	Ash's Noctowl	N/A
File:Ash's Phanpy Egg.png → →	Ash's Donphan	Ash's Phanpy
File:Ash's Larvitar Egg.png →	Ash's Larvitar	N/A
→	Ash's Swellow	Ash's Taillow
File:Ash's Treecko.png → File:Ash's Grovyle.png → File:Ash's Sceptile.png	Ash's Sceptile	Ash's Treecko Ash's Grovyle
	Ash's Corphish	N/A
	Ash's Torkoal	N/A
→	Ash's Glalie	Ash's Snorunt
→	Ash's Staravia	Ash's Starly
	Ash's Turtwig	N/A
	Ash's Chimchar	Paul's Chimchar
	Ash's Buizel	Dawn's Buizel
→	Ash's Gliscor	Ash's Gligar

	Pokémon	Alternate Names
	Misty's Staryu	N/A
	Misty's Starmie	N/A
	Misty's Goldeen	N/A
	Misty's Horsea	N/A
	Misty's Psyduck	N/A
File:Misty's Togetic Egg.png → →	Misty's Togetic	Misty's Togepi
→ →	Misty's Politoed	Misty's Poliwag Misty's Poliwhirl
	Misty's Corsola	N/A
→	Misty's Gyarados	N/A
	Caserin	Misty's Luvdisc
→	Misty's Azurill	N/A
→	Dewgong (Cerulean Gym)	Seel (Cerulean Gym)