As requested by Nimbusoak who wanted to see a Pokemon feature but Pokemon being such a huge franchise, lets divide this into two lists, to begin with Top 10 Pokemon.
10. Ash's Buizel
Featured as a main team Pokemon throughout the Sinnoh league and able to match the likes of Lucario, Buizel is always ready for any challenge.
9. Brock's Croagunk
Despite spending most of his time as a foil for Brock's flirting, Croagunk seems to serve the job better than Max & Misty previously, the look on his face is priceless.
8. James' Mime Jr
I wouldn't picture Mime Jr ever being part of Team Rocket but considering how childlike James' innocence could be sometimes it actually makes a lot of sense.
7. Mewtwo
As voiced by the great Dan Green, a tragic Pokemon who spent his birth process in a dreamlike world alongside a clone of Dr Fuji's dead daughter who was his only friend until she died during the cloning process, Mewtwo responded by killing everyone on the island in Pokemon's most brutal scene. His hate has subsided a bit since being free of Giovanni but makes a return in the latest movie to fight Genesect.
6. Meowth
Voiced by the late Maddie Blaustein, Meowth is the charismatic talking Pokemon of Team Rocket. Driven by love to talk and walk like a human and a hatred for his evolved form, Meowth will never grow any stronger but makes up for it with personality and frequently feels sorry for Pokemon who share his problems.
5. Ash's Charizard
He's here for one reason and one reason only, for someone of my generation who watched him refuse to fight and make Ash lose, told me that lead characters are capable of losing and made Ash a better character for it.
4. Dawn's Piplup
Dawn's Piplup is mostly here for facial expressions as they are some of the most priceless of the Diamond & Pearl saga. Piplup likes to pretend to be Dawn's knight and emphasizes that by refusing to evolve.
3. All Lucario
The most bad ass Pokemon of all time and the only non legendary to get his own movie, whether it be the companion of a knight or the fighting therapist of Gym Leader Maylene, Lucario has never been disappointing.
2. Ash's Infernape
Out of all the Pokemon owned by main characters not even Pikachu has had as much back story as Infernape did. Beaten to death by Zangoose and abused by his former trainer Paul, Ash trained Infernape into a huge power house that featured probably the best League match in Anime history.
1. Ash's Pikachu
But it's automatically clear who number one is, of course it's going to be Pikachu, I mean he is Pokemon. Grossly over powered and insanely loyal, don't expect the franchise to ever drop him from the series even if we fall out of favor for Ash.