Duke3D:
Alejandro’s Mapping Center
Mikko Sandt’s Duke Nukem
Duke Nukem Repository
Duke4.net
High Resolution Pack
Eduke32
Duke Plus
Thief:
TTLG Forums
Quake:
Func_Msgboard
Quaddicted
Team Shambler Map Reviews
Underworldfan’s Singleplayer Map Reviews
Quoth
Half Life:
Planetphillip
HL1 & HL2 SP Maps & Mods Polish Database
DooM:
DooM World
ZDoom Port
Tormenter667
Outpost of DooM II
Reviews / Blogs / Other:
Amphibian Mods
SP Map Corner
ShaDoW Design
Mod Headquarters
Mapcore