I'm going to go with Flash, but if you're on team LED, I'm fine with that, too
The Eleventh Hour's first ability can find any card with the Doctor creature type, not cards with the word "Doctor" in the name
Whenever any creature dies, Sephiroth drains life from an opponent
So its average selling price of $352 is understandable, but just like any other card on this list, if youre not aiming for the fanciest version of Cinderella, Melody Weaver, the non-Enchanted variant is available for a much more reasonable average price of $6
At best, this is awkward, and at worst it adds needless complexity to maintaining the state of the game
But to make that ability available for just two mana a tiny fraction of what might be available to a player at the time ensures that Time Walk can steal a match in completely unfair ways