Allowing a player to consistently return creatures from their graveyard to the battlefield with little cost is an absurdly strong ability
Once transformed, though, you are in good shape hitting for three unimpeded
In this green-blue-red deck, you can expect the unexpected when the Thirteenth Doctor and Yasmin Khan arrive
2/3 Cecil, Redeemed Paladin Legendary Creature Human Knight Lifelink (Damage dealt by the creature also causes its controller to gain that much life.) Protect Whenever Cecil attacks, other attacking creatures gain indestructible (Effects that say "destroy" don't destroy that permanent
(Or vary in their power enough that the user is uncertain what effect the card will produce during any one use.) The ability has cemented in black and is also used in red and artifacts quite a bit
Funeral Room // Awakening Hall Funeral Room is a bad Bastion of Remembrance, and Awakening Hall is a nerfed Rise of the Dark Realms