One of the tools I really like and have contributed to is Dave’s Mapper. Another contributor is Dyson, who does OSR style maps under a a limited non-commercial license. Simply put, you can use them for your own pleasure, but if you have a commercial product in mind, you need to contact him as he retains copyright for that purpose. In fact, it seems that Dyson started the recent geomorph random dungeon generators, so big thanks to Dyson! I like Dyson’s mapping style, and when using Dave’s Mapper, I use tiles made by Dyson Logos, myself, Risus Monkey, Dave Millar, and Infinite zerO.
Dyson has a Patreon campaign for his maps. He also has a Maps Archive and an Adventures Archive, mostly designed for Labyrinth Lord. He seems to have his own cottage industry going, because you can also buy a collection of the adventures and maps as Dyson’s Delves at Lulu or RPGnow.