jambarama wrote:one that can only really be played in EDH - it is too slow anywhere else (lets be honest, thragfire omnidoor was never a real deck).
Thragfire omnidoor did win a couple events, so it was, by definition, a 'real' deck. Besides, you can't judge something as being designed only as an EDH card just because no one has won a big event with it. That's like saying that Notion Thief was designed as an EDH card 
There are lots of cards that are playable in Standard, but not part of the 'top tier' deck metagame. Some have big, cool effects. The most recent pro tour had a couple cards that I saw being used that are considered 'EDH' cards...The GB enchantment that gets stuff back from your graveyard and the Red enchantment that makes whatever you cast random.
I would put that enchantment (Possibility storm) in the same category as Worldfire.