Okay, folks, it's confession time. I have no idea where you get maps like these. I jumped in and started guessing one day, since I enjoy maps and clues and the question to narrow things down reminded me of a Canadian game show called Front Page Challenge.
Is there a list of rules for this?
I am not sure there are any rules for posting maps, the only "rule" is not to do a google reverse image search of the posted map. You can go a long way by doing a google image search of '"something you are interested in" map'. I like using the
world bank development indicators which has a function to generate maps but it is not working right now for me. You have to select all countries (the tick in a box icon), then the series (the thing you want to map) and then the year. Another source is the
world in data that will make maps of loads of stuff.
[EDIT] Actually looking at the
first post there are some basic rules, but not that effect your choice of map.