Some of those maps are playable while other are only artistic maps. This page is to list all maps I found while browsing various forums which I found simply awesome 😀
Arbor Vitae by Philip Klevestav and Helder Pinto
Aqueduct by Mozi
DM-Primal by Ben Burkart
Dungeon Escape (UDK adventure level) by Chris Holden
Reclamation by Mozi
Solitude by Mozi
Zest Foundation by Thiago Klafke