I like
Allie (dislike
Ali),
Sandra, and
Xandra. My only problem is
Sandra and
Xandra sound almost the same when I say them, not sure if you have the same problem. I love
Sasha, but I see it as a masculine name, same goes for
Alex.
I think the best nickname is
Mireio's suggestion of
Ria. It's more unexpected compared to the typical
Alex's and
Lexi's. I have a friend named
Marie who goes by Rie so
Alexandria "
Ria" would work nicely for me.