[FOUND] A/B/O Omega Tony AU
Looking for a fic that came out around the first Avengers movie. It was an A/B/O fic where all the Avengers were Alphas or Betas. Except Tony who was an Omega, but was using scent blocker to pass as a Beta and no one knew. I'm can't remember what the primary pairing was, or if it was multiple pairings. I think it was primarily Steve/Tony. Anyway, something happens and Tony was outed as an omega and instead of rejecting him I think the other Avengers went into protective pack mode.
Updates: Found by Anon. It is "Feathers of Iron, Heart of Gold" by LittleStarredSky