Roguelike engines are not playable roguelike games but rather the underlying structure that can power one. They exist to allow people to easily write new games without the hasle of coding things like LOS code, object handling, RNG, ....
The known to exist engines are:
- T-Engine The engine powering ToME, made by DarkGod
- H-World a pure game engine by Hansjoerg Malthener, which he will use to make his own roguelike.
- JRLE The Java Roguelike Engine
Now, there might be others lurking around, if you find any, add it please!