In case you're involved in developing for the Atari ST, you may find my curated list of dev resources handy. If you have any useful links i can add, please let me know or create an issue in the repository! https://github.com/sandord/atarist-dev-resources
@sandor some YM stuff:
https://www.preromanbritain.com/maxymiser/
http://www.jchr.be/atari/ym2149.htm (French)
Other stuff:
https://github.com/ggnkua/half-sprite
http://ebook.pixas.de/index.php?frontpage
https://st-news.com/issues/st-news-volume-5-issue-2/education/optimizing-68000-code/
