RPG map resources

Editor software and web apps

️️Dungeon Scrawl - a web-based mapping tool with an old-school, hand-drawn look. Quick and flexible, but limited capacity for adding objects.
️️Deepnight Map Editor - another web-based map-maker, even quicker and simpler than Dungeon Scrawl and makes nicer-looking maps, but bad for indoor ones as walls have to be at least one square thick. You'd be surprised how much difference this makes when setting up lighting in roll20. Great for tunnels and caves and the outdoors though.
Dungeondraft - my current preferred "posh map" software. A desktop application that can be loaded with asset packs to create really nice-looking maps to be exported to your favourite VTT or printed out.

Hex Kit - great tool for quickly making hex maps, with some imaginative tilesets available for it, though sometimes ones apart from the official ones are hard to find. I have a Hex Kit tag and I made a free simple tileset for it.
Wonderdraft - by the same company as Dungeondraft, but designed for terrain maps of varying scales. I don't use this as much if at all, but it's nice to have.
Inkarnate - good-looking web-based map editor. Inkarnate can be used for battlemaps, but honestly, I didn't find it very good for them - it makes detailed, pretty, larger maps though.

watabou's generators: villages, islands, medieval fantasy cities, and one page dungeons (more on their itch.io page). These are great automated map creation tools, with plenty of configurable options.