With the release of Bloomburrow there are 20 Otter creatures ... you can get some big spells for free very early on. Vren, the Relentless does what Rats do best, keep pumping out tokens until ...

Bloomburrow introduces a new ... you get to make 1/1 Rat tokens that are effectively Relentless Rats equal to the number of creatures your opponents control that were exiled that turn.