Loosely based on this font by blazetype

It should work more or less as you expect it.

“#” is a sharp

Lowercase “b” is a flat

Lowercase “x” is double sharp

“bb” will create a double flat (conjoined via kerning)

Capitalised “ABCDEF” and “G” are the letter names

“i” and “v” acts as lower case roman numerals

“I” and “V” act as upper case roman numerals

“o-+” and “^” are their respective jazz symbols (dim, min, aug and maj)

“M” and “m” are as they are (for major and minor)

Capital “Q” is a q for quartal harmony

Lowercase “qwertyu” spell out the modes (sitting just below the number row; below 1 is Ionian, below 5 is Mixalydian etc.)

Capital “O” spells Oct for octatonics

Lowercase “d” and “a” spell out “dim” and “aug” respectively

0123456789 are there as expected

“/” for slash chords

() {} [] = <> != are all there (for those into pitch-class and set-theory)

Um, what else…

There’s “?” for those occasions you don’t know the chord

Also an apsersand “&” because I find that useful for notating polychords