Mappers for tabletop role-playing games, such as D&D, that are:
Dungeon Map Doodler is a free to use drawing tool accessible from any web browser. Easily create maps for your favourite tabletop RPGs in minutes!.
Dungeon Mapper is a map-making tool to easily create grid based maps for your computer games (dungeon-crawler,rpg) in browser and online publishing.
Tiamat is Web 2.0 Tile Mapper; Ideal for creating miniature scale maps for role playing and miniature games.
Tiamat is FREE to use to create maps. You only pay for the maps and tiles you want exported for personal use.
The software is still in beta.
RPG Map Editor is the new version of ANAmap, an online grid-based map editor for role-playing games with emphasis on simplicity.
Standard Action is a tabletop gaming application designed to be simple, but flexible. In game, Standard Action features an interactive game board, live chat, dice rolls, a turn tracker, customizable token stat bars, and much more. Game masters can take advantage of dynamic lighting, custom map layering, and organization of their maps into separate chapters to bring their game world to life.
Mipui is an online, grid-based map editor, with focus on simplicity and collaboration - all edits appear in real-time to other viewers.
It's intended to be used for role-playing games such as D&D and other tabletop games, useful both before a session as a mapper and during a session as a virtual tabletop. All maps are stored indefinitely in the cloud.
It can also be used as a virtual tabletop (VTT), since edits are live and it supports fog-of-war (with a line-of-sight reveal tool) and other VTT-friendly features.
Play any tabletop RPG remotely. As easy to use as your wet-erase mat: no cartographer degree required.
ANAmap is an online grid-based map editor for role-playing games, with emphasis on simplicity.
Dungeon Painter is a free powerful encounter map design tool.
Design and print RPG game maps on any device with thousands of maps instantly available for your use.
Disclaimer: the list owner is the author of Mipui.
I love your list! I had never heard of Standard Action before, I'm looking forward to checking it out. I do request adding Dungeon Scrawl to the list if you want; it may be newer, but it has a lot of features that make it pleasant to use.
Added Dungeon Scrawl and Dungeon Map Doodler, two excellent new editors. Also added Shmeppy and the new version of ANAmap.