Outlines of different countries which make lovely island shapes
https://www.worldmapsonline.com/map-outlines
Open-source app for creating simple grid-based maps for games
https://www.mipui.net
More sophisticated online map-making platform
https://inkarnate.com
Fantasy map creator
https://azgaar.github.io/Fantasy-Map-Generator/
City map generator
https://maps.probabletrain.com/#/
