Allen Iverson -- I'LL SOCK YOU OUT ... I'm Back In Endorsement Game

Allen Iverson's endorsement drought is finally over -- the ex-NBA superstar just landed a brand new deal with a sock company ... TMZ Sports has learned.

Iverson was one of the most marketable guys on the planet during his heyday -- but lost a bunch of his deals during his infamous fall from grace.

But A.I. has been on a serious rebuilding campaign recently -- appearing on morning shows and promoting a new documentary -- and now, he's got a new endorsement campaign to boot.

The deal is with Stance -- which signed the 39-year-old to a multi-year contract to be a spokesperson alongside NBA stars Dwyane Wade, Klay Thompson, Chandler Parsons and Andre Drummond.