Pepper + Natasha
Pepper wouldn't have been the first to assume that Clint and Natasha were in a relationship but it turned out they were proof that a man and a woman could be best friends without anything more. Natasha got on incredibly well with Laura and the two were firm friends as well. Having what Clint and Laura had together hadn't ever been something Natasha imagined for herself but she couldn't say she wasn't enjoying it.
"We've asked her about it and given her time to think. We aren't going to push her but we're both very much hoping it's something she wants too" And having Alexander confirm she was adopted in his version of the future just made it seem right somehow.