Lifecreed Duo
Champions from Beyond feels like a dream for token brewers, letting you flood the board, scry, and eventually punch faces with a pseudo-Overrun
Gimbal, Gremlin Prodigy wants you to make artifact tokens with different names, while Rashmi and Ragavan let you cast your opponents' spells for free so long as their mana value is less than the number of artifacts you control
Since were choosing The Swarmlord, well focus on additions that enhance the +1/+1 counter theme
Because Vivi's mana ability can only be activated on your turn, you can use it to cast big spells, and leave your lands open for counterspells or protection spells to keep Vivi alive until your next turn
Black can play a bunch of synergistic artifacts, and MDFCs like Malakir Rebirth to boot