Technically with enough mana you can go through your entire deck, but short of generating infinite or near-infinite mana you'll eventually run out if you don't hit something good
It's an interesting reanimate/ramp target, and with certain commanders like Kinnan, Bonder Prodigy youll filter all that mana into cards
I believe priority should be on getting creatures into the graveyard through destroy, sacrifice, or -X/-X effects
Endbringer: A pinging, card drawing, pacifying eldritch abomination that untaps itself each turn is very strong
It is more intertwined with the IP than just making a TCG off of a whim
Black for Common, Silver for Uncommon, Gold for Rare, and Red-Orange for Mythic Rare