I like
Charles. It's a little formal sounding on its own, although I think it sounds fine once the child is an adult. It's a bit heavy on a child, if you know what I mean. Personally, I like the nn
Chaz. I think it's fun.
Charlie is cute too, but it works a lot better on a child than on an adult. An adult with the name
Charlie really has to have the right personality to pull it off.
Charles AnthonyCharles DonovanCharles JulianCharles Nathaniel
I think a lot of names work with
Charles, although I seem to like three syllable names that are slightly less classic and common.