I don't remember reading many of those, maybe a few with Hild married to Ranma or is his mother. The one's I can quickly find are:
The Merger By: deathgeonous
The Rebirth of the Daimakaicho By: deathgeonous. Rewrite of The Merger
Runner up, I think Ranma takes Hilds place. I think Hild is still fine just retired.
Daimakaicho Ranma By: Tuisto