So... Yisan is basically [mtg_card=Aether Vial] + [mtg_card=Birthing Pod]. That's pretty nasty, though the 2G per turn may get expensive. He can also slot nicely into Monsters or Jund, and should be quite lovely for just about any Commander deck that plays Green, potentially very powerful as a Commander himself.
Speaking of Commander, Ob Nixilis, Unshackled can be positively obscene, especially if you really, really hate Green or Blue. Too expensive and not very impactful for Standard, probably... at least with [mtg_card=Desecration Demon] still around. I wonder... is there a way to make other players search their libraries for some sort of benefit? one of those "group hug... TO DEATH!" deals?
Spirit Bonds has potential to get crazy... too bad they added "non-token" instead of "non-spirit", but hey... [mtg_card=Brago, King Eternal] is a thing now, as is [mtg_card=Obzedat, Ghost Council].
Avarice Amulet looks like it'll fit into whatever becomes the next Bant Hexproof. It's everything Hexproof wants in an equipment, and the downside isn't that big a deal when you don't have to worry about spot removal (and are likely packing some of your own)... too bad it costs 4 instead of 2 or 3.
Speaking of M15 spoilers... have you seen Nissa, Worldwaker [http://sales.starcitygames.com/carddisplay.php?product=698630]? dang! also, new Ajani and new Jace... not bad. I can't wait to see what other 'walkers M15 has in store, considering the strong hints that Sorin, Karn (or a Karn-like entity), and especially Garruk will be returning as well.