I would love to play again either Remus or Sirius. If you’re okay with an age gap, I have a plot bunny involving Daphne Greengrass against either of them. The premise would be that Daphne, who has come from a family similar to Sirius’, had chosen the Light side during her years at Hogwarts, helping to feed information. Post war, she’s trying to avoid those who are still about who hold a grudge and make it on her own since she’s been disowned by her family. Assuming either or both men survived, she might be staying at Number 12 and things can go from there.
Or, alternatively, if you would be interested in a time travel theme involving Daphne and either wizard.