Unicron, Galactus, doesn't have the Matrix of leadership to bust Unicron up. Sailor Mercury or Rei from Evagellion (sp)
Yo Joe! Well he was a Joe for a bit before they made him a bad guy again. Snake Eyes vs Ryu (Street Fighter)
Naruto is virtually a demi-god at this point. Naruto stomps Gray Fox (Metal Gear Solid) vs Genji Shimada (Overwatch)
Alduin. Not only is he the most powerful dragon on Nirn, he's also extremely intelligent and cunning. Pennywise vs the Killer Klowns from Outer Space.
Pennywise because he probably smells like raw sewage!! Mewtwo Vs. Professor Xavier in a psychic battle
Samus. She's taken down entire planets, and has killed thousands of cybernetic warriors. Master Chief vs Boba Fett.
Master Chief, Boba would die the same death his old man did. The Death Battle team vs The Epic Rap Battles of History Team.