Stony: they got together after AoU. Tony had surprised Steve with a baby from Pepper. Steve met her when he went to convince Tony to help them with the time heist.

Superbat: A LoA (not talia?) ex of Bruce had a baby and after her death, the baby was sent to Bruce. Bruce had no idea how to take care of a child. He took her to Clark's farm. Clark took care of her. And then him.

WinterWidow/CaptainWidow/BruceNat: Nat was in an earlier BW group than Yelena so her medical procedure was different. She was able to conceive with super serum sperm.

Idk who else to do atm