Post-getting Bucky back (Civil War or AU or whatever interpretation) the most non-SHEILD, kind of friendly, contact that Bucky has is Steve, Sam, and Natasha. They tell him about the Avengers, some of the people in their lives. Then slowly Bucky is introduced to the world.

Clint Barton is not as advertised.

(Could be pre-Clint/Natasha and Natasha is oblivious or in denial and Steve is oblivious, or Bucky/Clint,or Bucky/Natasha/Clint with established Clint/Natasha, or gen fic. Just Clint Barton being hard to pin down. Or maybe Nat was just trolling.)