* Sprites are composed of [layers & frames](http://www.aseprite.org/docs/timeline/) as separated concepts.
* Support for [color profiles](https://www.aseprite.org/docs/color-profile/) and different [color modes](http://www.aseprite.org/docs/color/): RGBA, Indexed (palettes up to 256 colors), Grayscale.
* [Animation facilities](https://www.aseprite.org/docs/animation/), with real-time [preview](https://www.aseprite.org/docs/preview-window/) and [onion skinning](https://www.aseprite.org/docs/animation/#onion-skinning).
* [Export/import](https://www.aseprite.org/docs/exporting/) animations to/from [sprite sheets](https://www.aseprite.org/docs/sprite-sheet/), GIF files, or sequence of PNG files (and FLC, FLI, JPG, BMP, PCX, TGA).
* Pixel-art specific tools like filled [pixel perfect freehand mode](https://twitter.com/aseprite/status/427135197671591936), [shading ink](http://www.aseprite.org/docs/shading/), [outline](https://twitter.com/aseprite/status/1126548469865431041), etc.
* Tiled drawing mode, useful to draw patterns and textures.
* Undo/Redo for every operation and support for [non-linear undo](https://imgur.com/9I42fZK).
* [Transform multiple frames/layers](https://twitter.com/aseprite/status/1170007034651172866) at the same time.
* [Reopen closed files](https://twitter.com/aseprite/status/1202641475256881153) and [recover data](https://www.aseprite.org/docs/data-recovery/) in case of crash.
* [More features & tips](https://twitter.com/aseprite/status/1124442198651678720)
* [ENDESGA Studios](https://twitter.com/ENDESGA), [EDG16 and EDG32](https://forums.tigsource.com/index.php?topic=46126.msg1279124#msg1279124), and [other palettes](https://twitter.com/ENDESGA/status/865812366931353600).
* [Adigun A. Polack](https://twitter.com/adigunpolack), [AAP-64](http://pixeljoint.com/pixelart/119466.htm), [AAP-Splendor128](http://pixeljoint.com/pixelart/120714.htm), [SimpleJPC-16](http://pixeljoint.com/pixelart/119844.htm), and [AAP-Micro12](http://pixeljoint.com/pixelart/121151.htm) palette.
* [RotSprite](http://forums.sonicretro.org/index.php?showtopic=8848&st=15&p=159754&#entry159754) by Xenowhirl.
* [Pixel perfect drawing algorithm](http://deepnight.net/pixel-perfect-drawing/) by [Sébastien Bénard](https://twitter.com/deepnightfr) and [Carduus](https://twitter.com/CarduusHimself/status/420554200737935361).