Initially there was rltiles (http://rltiles.sourceforge.net/). This was/is a set of public domain 32x32 tiles for Crawl and Nethack. 

Over time these were extended, modified, and new tiles were added. Much of this work was done by the Crawl, and, later Crawl Stone Soup team (http://crawl.develz.org/wordpress/). For a long time, these changes/additions were under the "Crawl" license, unable to be used by most other projects. 

The wonderful developers/artists who work on Crawl Stone Soup have signed off their copyrights on the tiles enclosed in here, returning them back to a state similar to public domain (CC Zero, see LICENSE.TXT). They are free to use for any purpose. However it would be nice for those using them to credit the developers/artists, and state where you recieved them so others may find and use them as well.

Also available at:
 * https://github.com/crawl/tiles/tree/master/releases 
 * https://opengameart.org/content/dungeon-crawl-32x32-tiles 
 * https://opengameart.org/content/dungeon-crawl-32x32-tiles-supplemental
 
CREDITS:

The following is the list of artists that gave approval in 2010 for their artwork to be released under CC:0. It is asserted that this covers any new art submitted to Crawl. Please contact the maintainer (chris.hamons@gmail.com) if this is incorrect.

- Eino Keskitalo evktalo@users.sourceforge.net (evktalo)
- David Lawrence Ramsey dolorous@users.sourceforge.net (dolorous)
- Enne Walker enne.walker@gmail.com (ennewalker)
- Poor_Yurik
- Stefan O'Rear stefanor@cox.net
- Jude Brown bookofjude@users.sourceforge.net
- Ixtli cg@325i.org
- Robert Vollmert rvollmert@gmx.net
- abrahamwl abrahamwl@gmail.com
- dshaligram 
- Jesse Luehrs doy@tozt.net
- David Ploog dploog@users.sourceforge.net (dploog)
- Mitsuhiro Itakura
- coolio
- Denzi
- Adam Borowski kilobyte@angband.pl (castamir)
- Porkchop
- Johanna Ploog j-p-e-g@users.sourceforge.net (j-p-e-g)
- Jinhlk
- rsaarelm
- Totaku
- Purge
- LoginError
- zebez
- n78291 (Shayne?)
- Charles Otto ottochar@gmail.com (caotto)

The following artists have given explicit approval that past and future artwork submitted to crawl is under CC:0.
- ontoclasm yokomeshi@gmail.com
- Neil Moore neil@s-z.org (|amethyst)
- donblas/chamons chris.hamons@gmail.com
- CanOfWorms
- minmay
- gammafunk
- Grunt (sgrunt hypergrunt deathgrunt Steve Melenchuk - smelenchuk@gmail.com)
- curio.solus@gmail.com (Curio)
- Raphael Langella raphael.langella@gmail.com
- Brendan Hickey - brendan@bhickey.net
- Nicholas Feinberg - pleasingfung@gmail.com (PleasingFungus)
- shmuale (wheals Shmuale Mark - shm.mark@gmail.com)
- Edgar A. Bering IV - trizor@gmail.com
- Florian Diebold flodiebold@gmail.com
- dolphin
- cjo
- Brannock
- floatRand
- XuaXua
- Mu muuuuu@gmail.com
- Omndra
- co
- Baconkid
- Eronarn
- xnmojo
- fusentrap
- frogbotherer - therealchriswest@hotmail.com
- pubby pubby8@gmail.com
- Corin Buchanan-Howland corin@buchananhowland.net
- Raumkraut
- roctavian - sicsemperjohn@gmail.com
- Marbit
- theTower mwclaws@gmail.com
