This is from macOS, but copy/paste might just work for anything:
♭
MUSIC FLAT SIGN
Unicode: U+266D, UTF-8: E2 99 AD
♮
MUSIC NATURAL SIGN
Unicode: U+266E, UTF-8: E2 99 AE
♯
MUSIC SHARP SIGN
Unicode: U+266F, UTF-8: E2 99 AF
♭
MUSIC FLAT SIGN
Unicode: U+266D, UTF-8: E2 99 AD
♮
MUSIC NATURAL SIGN
Unicode: U+266E, UTF-8: E2 99 AE
♯
MUSIC SHARP SIGN
Unicode: U+266F, UTF-8: E2 99 AF