If you've got the mana to burn, suddenly you can start paying the untap cost to make multiple Servos, Thopters, or Constructs per turn
Don & Raph, Hard Science | 1 Colorless Mana, 2 Hybrid Blue/Red Mana Legendary Creature Mutant Ninja Turtle Menace Whenever Don & Raph attack, the next non-creature spell you cast this turn has affinity for artifacts
But I would note how nice it is to get the second half of a land cycle one set after it was introduced
Bicycle Lands Any dual land that can be tutored for with a fetchland automatically gets a second look from me
Rooms actually trigger eerie twice once when the first door is unlocked on the initial enter of the Room, and again when you unlock the final door
It occurs to me I might want to put this in my Yasova Dragonclaw deck