Tom Wrench's Ranma stories. This includes "Proper Punishment" which I enjoyed quite a bit.
A multiple anime fiction site. There are some stories that fit cannon here and some that don't.
This page is about the life of Akane and Ranma when they get married and go to college.
Digital Knight Communications
This page is about how Nabiki's life goes after she starts
to develop a life of her own. There is also some continuation to the rest
of the
cast.
This Page has some good cannon stories.
Lord Archive's Ranma Fan fiction Page
I must say that this series is GREAT! It has the unique
concept of talking to Akane after the facts of the events the characters
are talking
about it also introduces new characters and new chapters come out fairly
regularly.