Thecla

Saint Thecla is one of my favourite saints. Highlights of her story include befriending a lioness, baptizing herself in a pool full of seals (yes, the animal), and being ride or die for Paul to the point that she died on his tomb.
I don't love the name for a baby (at least in an English-speaking context) but I think it would be an awesome middle name, or else a cool name for a pet or fictional character.

I met someone with this name today! I'd never heard it before. Pretty cool name!