“Beauty and the Beach”
In this episode Misty and Team Rocket enter a beauty contest. James dons inflatable breasts and trolls Misty by saying “Maybe when you’re older, you’ll have a chest like this!”.
The Porygon episode
The animation of Pikachu’s thunderbolt attack caused seizures in kids. ‘Nuff said.
“The Legend of Miniryu”
In this episode guns are repeatedly pointed at other characters in a threatening manner.
Also, Meowth dons a Hitler-esque mustache.
Episodes with Jynx in them were originally unaired because Jynx looks like a blackface caricature of Africans. Later on Jynx is re-colored purple.
If you Google “banned pokemon episodes”, you will find other websites (e.g. Wikipedia) with more information on which episodes were finally aired after changes were made to them.