He-Man on Battle Cat
Orko
Anti-Eternia He-Man
Anti-Eternia Orko
Evil Warrior's Slime Monster
The Anti-Eternian versions of He-Man and others were introduced in a German audio drama and a few pieces of artwork, Skeletor opened a portal to the Anti-dimension which brought the evil doppelgangers to Eternia!
"Good" versions of Prince Keldor and other Evil Warriors were also mentioned but not in much detail compared to He-Man etc.