Rap Battles I parodied last season (Besides Darth Vader VS Hitler & NicePeter VS EpicLloyd)

Bruce Lee VS Clint Eastwood
Adam VS Eve
Gandhi VS Martin Luther King JR.
Nikola Tesla VS Thomas Edison
Lance Armstrong VS Babe Ruth
Billy Mays VS Ben Franklin
Master Chief CS Leonidas 
Mr.T VS Mr.Rodgers.
Cleopatra VS Marilyn Monroe
Napoleon Bonaparte VS Napoleon Dynamite
Gandalf VS Dumbledore
Frank Sinatra VS Freddie Mercury
Sarah Palin VS Lady Gaga.

Characters in future battles:

Fluttershy
Photofinish