You should also check out #Mapvember by Miska Fredman. On https://www.miskasmaps.com/mapvember/ you can participate in an open challenge for all who enjoy drawing fictional maps for roleplaying games.
These maps can be anything from dungeon maps to geographical maps, from fantasy to science fiction, as long as the maps are usable without other maps, tools or information.
This is not a competition, so there are no winners or losers. But hopefully, there will be a bunch of inspired people with a burning desire to draw more maps or use the maps shared by others in their own games.