Hexen II / HexenWorld DeathMatch Map Pack: A collection of multiplayer deathmatch maps, by various authors, for Hexen II / HexenWorld, includes most maps run by HexenWorld servers. This edition is a revision of ACE's HexenWorld map pack, and includes graphical and map design glitch fixes in several maps. Newer and older (original) versions of the maps are cross compatible, that is, a client and a server may run different versions without any significant problems. Collected by Pa3PyX, they're available for download here.
Baliseta's Page * has download links to some maps for different types of gameplay: Single Player, DeathMatch, Siege and Capture the Flag.
DarkRavager's Site has a couple of maps and prefabs (parts of maps for further use).
The HexenWorld Forge had a collection of maps and prefabs, plus dozens of new textures to use for your levels. The site disappeared at the latest reorganization of raven-games.com so you might want to ask there or try to contact the author of the site at korskarn@sympatico.ca.
The Joust has a tutorial on how to build maps with WorldCraft 1.5.
DarkRavager's Site has a mapping tutorial.
A complete guide of all entities for reducing your problems when editing maps.
http://www.planetheretic.com/h2entities/
*: This link is not avaiable