@ankiadict I also have the ULX3S and had quite some fun with it. Also the mentioned examples are really nice. For advanced stuff I really like this collection (
https://github.com/emard/ulx3s-misc - or other repos from emard).
Recently I adopted the GateMateA1-EVB from Olimex. It's very nice too and everything open source. There ain't as much resourced for it yet, so maybe not that beginner friendly, but for 50 bucks a nice product