She also did quite a few guest appearances in DS9 - she was in love with Odo. Both have sadly passed.

Nurse Chapel, and "Number One"* from the original series' original pilot, The Cage. Both of these characters are main cast in SNW, sadly no mind-swap plot with these two has happened yet.

* I don't think she had a full name at that point?

Didn't realize she played Lwaxana Troi. Knowing that now I wonder, am I going to hear the ship's computer as Lwaxana?