I adore
Kat. I prefer
Katherine to
Kathleen, but if I'm being really nitpicky, I'd go with
Katharine. :)
Katarina "
Kat" is a favorite of mine as well. I like
Kathleen without a nickname.
Jeana is pretty, though I prefer just
Jean. Snappy.
I love
Matilda as well. In fact, I think a combo of mine used to be
Jean Matilda!