In anime, I think it might be Ed X Rose.
Because they are better than Ed and Winry combination.
Ed and Winry are more like siblings more than potential lovers.
I have the best couple.
Al X Katherine Armstrong.
I know they did not meet before.
I think they might be introduced each other by Alex Armstong.
And, Katherine said that she like some one like her brother.
Al is the best choice at this point , but he has no body.
And, Al is a better alchemist than his brother.
Hmm. Maybe, we should start Poll about this issue.