The only one I've ever met is a
Drea (dray-uh).
Tor and Kel seem like natural shortenings, but some of these are really goofy. Eck, Prill, and Sabeth? Lol. I think adding -z/-za to the end of a short version of the name is a British thing, so that explains
Gaz, Gazza, Jezz, Muzza, etc.