mtg all cards A magic corner of the Universe: permanents are creatures Every MTG card ranked :

As long as The Wandering Emperor entered this turn, you may activate her loyalty abilities any time you could cast an instant

The biggest danger is that almost every deck sideboards Karn, rather than that Karn just beats everyone, and I think theres a good chance that wouldnt force them to ban Karn, although theres a small chance that that would push the price of Karn high enough to chase some people out of the format.

Giant Oyster, and Abbey Gargoyles get honorable mentions as they did see some play in the early years of the game

(8/23/2016) At the end of the game, you must reveal any face-down conspiracies you own in the command zone to all players