Sources include various lists on the Internet, as well as the current Wikipedia page at https://en.wikipedia.org/w/index.php?title=List_of_ID3v1_Genres&oldid=896774343 but most importantly the list as used by taglib at https://github.com/taglib/taglib/commit/3e60e339a4bc46e2a1a7aea782502480561a8acf#diff-f86455366624350770f41b4940925dde
Further patches to harmonize the spelling have been sent to taglib and libid3tag. See also https://github.com/taglib/taglib/pull/942/
60d599e217 libavformat: fix spelling in ID3v1 genres and extend the list of Winamp extensions.
libavformat/id3v1.c | 58 ++++++++++++++++++++++++++++++++++++++++++++++-------
libavformat/id3v1.h | 2 +-
2 files changed, 52 insertions(+), 8 deletions(-)