Zeth
From ZDoom Wiki
ZETH is a level editor designed exclusively for ZDoom, based on DETH (which was in turn based on DEU) by Jim Flynn. Currently runs in a DOS environment, but a Windows/Linux version is also in development. This development version is currently the only level editor for Linux which supports ZDoom level editing features.
DOS Version: http://www.zdoom.org/download.html
Windows/Linux Version: http://forum.zdoom.org/viewtopic.php?t=799

