The world could use an open-source project to manage restaurants; content management backend, let people add in all of their menu items with photos, descriptions, etc. and then surface that to the website (or not). Mobile app support, iPad- or web-based ordering (for servers or customers), Skip/DoorDash/UberEats integration, or self-managed delivery could all be potential for-profit addons, as well as hosting and consulting. This is something that I could potentially see people liking and using, and could also turn into a potentially profitable business.

I play D&D a lot; it would be nice if there were an e.g. AndroidTV or AppleTV app that could display maps, including with fog-of-war, etc. I tried to do stuff like this with existing tools and had a really hard time lining up the existing grids on battlemaps with what the software understood to be the grids in the software (used for calculations). This one would require a GM interface to show/hide areas, active stuff, whatever. No idea if it would be fun to build (maybe use computer vision to detect battlemap grids?) but it's a thought.