Derevi, Empyrial Tactician A+ Speaking of Derevi, the legendary bird wizard is easily one of the most powerful and at times broken commanders in the format
For me, though, the joy comes from building your own and squaring off against real people, though there is a deck-building function to help you assemble something if you dont wanna do all the work yourself
Blue players don't need much of an introduction, mostly because they've already interrupted yours with a Counterspell
While that card is exiled if you don't have a legendary Vampire in play, Olivia can be a great way to cheat massive high-impact threats into play if your deck has an easy way of putting them into the graveyard
Having a creature with four or greater power is easy when Rhonas can pay 2G to give a friendly creature +2/+0 and trample, and Bontu can sacrifice a creature to scry 1 and drain one life from each opponent