Well, As for Movepool , its quite obvious:Smeargle. Using sketch he can learn any move. Unfortunately unless you have a friend willing to use a certain move , its very hard to get the right moveset.
And as for being able to perform many different roles-Tyranitar/Dragonite
Both can be sweepers of physical or even special capabilities,and both can be tanks, as well as walls if your team calls for it.