During her time as a SHIELD agent, planted by Loki, Sigyn (Agent Astrid Tyson) was on a mission of sorts with Clint, where he found himself temporarily detained till SHIELD had her retrieve him.
AU - Thor goes kill crazy on Midgard, and S.H.E.I.L.D. calls Loki (who is a nice guy) to help stop him from blowing shit up.
Clint/Natasha Domestic-ish AU - they’re basically the same but they have a five-year-old kid and Clint owns a diner.
Clint: (on the phone) I love you too, Iron Ass.
Natasha: What does that son of a bitch want this time?
Phillip: Mommy, what’s a bitch?
Natasha: It’s a girl dog, honey.
Phillip: How can Uncle Tony’s mom be a dog?
Natasha: Just finish the cereal Daddy made.
Banner: But why me and why Sesame Street?
Coulson: Well, they are colorful creatures. You know… like… the Other Guy.