If only it were not restricted to allies, but thanks to Constructed, I can go outside of the Avatar: The Last Airbender set and slot in some choice cards in Turntimber Ranger, Angel of Renewal, or Halimar Excavator
While I like the fact it makes tapped treasure for balance purposes, it does nerf the card in a way that might mean its too slow
Ledger Shredder, Esior, Wardwing Familiar, the new Senu, Keen-Eyed Protector
This may seem like it's not that productive, as your opponent will often die to regular damage first, but a lot of what makes poison counters special in Phyrexia: All Will Be One is the Corrupted mechanic, which is an ability word that turns on when your opponent has three or more poison counters
What's your favorite Grixis card that missed the list
You also set up the persist combo automatically with Celes around (e.g., Murderous Redcap + Viscera Seer), and it rewards you for going wide with creatures, if you prefer the fairer route