If they are particularly ugly : Tarmo & Goyf
If they fight all the day: Urza & Mishra (if one is a female: Chandra & Jace - if one is good and the other is evil: Gerrard and Yawgmoth )
If instead they collaborate: Brainstorm & Fetchland
If they always seem to listen to you, but in fact they don't: Maro & Aaron
If they have tentacles: Cthulu & Emrakul