Word for "letter or letter-like character"?
From The Go programming Language - Package unicode
func IsLetter(rune int)
bool IsLetter reports whether the rune is a letter (category L).
I therefore suggest the category word OP seeks is simply letter.
A glyph is a symbol that is an element of the language you are writing in. There term pseudo-glyph denotes marks that should look like an element of the language but are not.