Pyxel Edit is a tilemap builder and tile editor.
Ranked in these QuestionsQuestion Ranking
Pro Supports animations
Tiles can be animated within Pyxel Edit, with "onion skin" frame overlays to assist in making smooth frame transitions.
Pro Tileset extraction
Given an image and specified tile dimensions, Pyxel Edit will extract a tileset with no duplicate tiles. This mostly works for flat images though. If you feed Pyxel "finished maps" you will still get a lot of duplicates.
Pro Intuitive UI
Pyxel Edit is widely acclaimed for its ease of use.
Pro Tilemap serialization support
Tile-based images (maps) built in Pyxel Edit can be serialized via XML or JSON for easy import elsewhere.
Pro Cheap compared to others
For only $9 (£6), this is one of the cheapest but also one of the best pixel editors out there.
Con Free version lacks features
The free version of Pyxel Edit is an outdated beta. It does not receive updates.
Con Mac version is dependent on Adobe Air
The OSX version of the application requires Adobe Air to run.