On to the activated ability, is a nice easy cost, and while the nonlegendary clause is sure to nip at you a couple of times for interactions you would love to have, there are lots of excellent targets for Niko to flicker and result in three or more extra white or blue ETB effects, just look at Karmic Guide, Trinket Mage, and Junk Winder
If you do, return each other card exiled with mimic vat to its owner's graveyard
Grove of the Burnwillows (EOS) $7.39 Grove of the Burnwillows is a fun nod to MTGs past, as giving your opponent 1 life can be better or worse than losing 1 life yourself based on how aggressive or controlling your deck is
Also, he costs three mana for a 2/3 with no particularly noteworthy combat potential
Heliod, the Radiant Dawn / Heliod, the Warped Eclipse Heliod, the Radiant Dawn is just an oversized Auramancer, but transform this baddie and you get Heliod, the Warped Eclipse, a Phyrexian god that converts opponents card draw into cost reduction for your spells
Your opponent is likely to possess many artifacts, particularly with the Fallout set, so slinging out multiple copies of Powder Ganger keeps their artifact count in check whilst ensuring your go-wide strategy sticks
