i'd guess
Mare or
May. you can use
Molly and
Polly as well.
Mitzi can be used for a pet form of
Maria (although i beg you, please don't use it on a human!)
there are lots of variations of
Mary (
Marie) though you might like to consider:
MaraMarah
AmaraMaleia
Maliana
Maraea
MariaMariahMarianMarianneMarielMarielleMariellaMarionMarilynMarisolMerissa
Miriam