Pokémon - the ubers in nutshell

Mega Aggron: Nokia.

Facepalm

These are simply the pokemon you would normally find in the Ubers metagame. Just because they're not banned from the lower tiers, it doesn't mean they aren't viable in the higher ones. To illustrate, Ditto is in the lowest tier (NU), but is actually more common in Ubers than in any other tier, simply because its ability to transform is more useful the stronger its opponents are.