One of my favorite things is interesting nicknames for more formal given names — the more interesting the better.
I recently read about the nickname “Ish” for Aloysius, which I’d never heard before. And nicknames for Elizabeth, which might win the prize for most numerous of any name, are discussed here, with a link to a longer list here. Some of my favorites: Tess, Betsey, Liza, Ellie, Liesl/Liesel, and Liddy. And I know of an Elizabeth nicknamed Libbet.
Do you know of any interesting or unusual nicknames for more formal given names?