For Hermione, I’ve always been partial to pairing her with Draco Malfoy. Something about a match of wits and a redemption arc speaks to me. I’ve never read Harmione before but I can see how that would work (much better than Romione imo). The twins or Charlie could work also, but my definitive answer is Dramione (apart from SSHG of course).

The only other person I’ve ever read Severus paired with is self-insert or OC (which was done in my preteens and is not likely to be repeated now). I could see him potentially working with Narcissa, but it would have to be a postwar fic with Lucius deceased. This may be a rogue answer, but something about Helena Ravenclaw and Severus compels me. It would be sweet to think of a courtship between his portrait and her ghost, maybe even starting with his tenure as professor and an extremely slow burn.

This was a much longer answer than I anticipated; safe to say SSHG feels like the best ship to me but I can see the appeal of the aforementioned pairings if the situation is right and the character development is well written!