I have participated in the following games:

Worldspinner  

kickstarter https://www.kickstarter.com/projects/worldspinner/worldspinner-fantasy-rpg-worldbuilder-and-map-make 
Worldspinner is not just a mpa creator but also a worldbuilder (adding races, historie etc.)
Website: http://worldspinner.com/ (currently alpha, soon in beta)

for alpha testers (if you have the rights) http://alpha.worldspinner.com/
check also https://drunkennerdery.com/ (Drunken Nerdery)