My sister is an Elizabeth, but always called Beth. (Our grandmother sometimes calls her Bethel in a joking/affectionate manner but I had no idea it was a real name!)There are so many variations and related names. What about Elspeth, Elsabeth, Lisbeth or even Marybeth?
I had thought about Elspeth because I love it but then thought no because it doesn't contain the Beth partElsabeth is cute but I still don't feel I love it