Dominaria United features a plethora of useful common cards, with some boosting up already powerful archetypes, and others capable of reviving older ones
Of course, they could exert for other reasons and avoid having to challenge, but if you can get something big enough of your own exerted, your opponents characters will crash against it and take themselves out
The other Commander you can use is Mr
This is a 60 card, blue/white flying deck
The upside in the case of Psychic Spiral being that we also give ourselves the ability to regrow any powerful effects we may have lost, even if it doesnt mean we are ending the game in the immediate future
Happy fawning, deckbuilders.