Some EDH decks built around delirium can still make use of Grim Flayer, especially if you can put the surveil 3 ability to good use
Its basically a permanent thats also an edict effect that cant miss
The blue in the deck is a very light touch, dipping into the Blue-Black zombies from Amonkhet (Gleaming Overseer, Spark Reaper) and Innistrad (Havengul Lich, Diregraf Captain, Champion of the Perished), as well as a handful of counterspells (Sinister Sabotage, Undermine) and card draw (Distant Melody, Deep Analysis)
This spooky guy does a bit of everything
If they do not, Ursula will bury them under an incredible amount of value
The other thing that's going to keep this deck humming along is of course cheap token creation to consistently proc our Ally triggers