Help find mind-mapping/flow chart software

Does anyone know of any good “mind-mapping” or “flow chart” software that’s free? I’m using it for planning a city design. I want each node to represent a city area and the noodles to represent a connection between the areas. What would be the right type of software to achieve this? Can I do this in Blender easily somehow? I tried doing it with the shader editor and it crashed the program, possibly because the node network didn’t make any sense as a shader…

Side note: I added a “diagram editor” feature request on Right-Click Select to make mind maps. People don’t seem to like it for some reason…