Way more than three picks for the top spot, nearly every card playable
Enchantment Kozilek's Unsealing Devoid (This card has no color.) Whenever you cast a creature spell with mana value 4, 5, or 6, create two 0/1 colorless Eldrazi Spawn creature tokens with "Sacrifice this token: Add ." Whenever you cast a creature spell with mana value 7 or greater, draw three cards
For example, Charizard would normally be a Stage 2 card, and the player would need to place a Charmander on the Bench or Active position and evolve it into Charmeleon before it could then be evolved into Charizard
You might use this in the 99 to exploit creatures with busted enters abilities like Etali, Primal Conqueror or slap it in the command zone to see how many copies of Fanatic of Mogis you can create
Red has plenty of ways to rummage and loot through their deck, so it comes online quite easily
As the saying goes, if there are still two left they are valuable, if there's only one it is priceless