The Best Custom Campaigns in my Opinion:
1. Yama: is great map if you like japanese culture since this map is based in Shubuya(japan)
2. Diescraper: A cinema, a little mall and vip suites this map have it all and have an standart level of difficultty
3. DeadCity II : possibly this map was intended to be unwinnable at all,I remember playing with a friend this map, he was dealing with two tanks in the front of the street and i was fighting with a crescendo horde in the back, until we run off of space and they crushed us, still was fun
4. Farawell Chenming: another super hard level designed to troll players with an insane amount of zombies spawning everywhere, when you are traveling in the streets, zombies jumps of the adjacent buildings and windows, also the military drops munition for you randomly in the city , that was very fun in my opinion
5. Death before dawn: Based in the movie dawn of the dead this is a must have campaign
6. Dead Series: based in the cult movie day of the dead, it have a good amount of gore scenarios like in the movie
7. Blight Path: it features original special infected and music in this campaign, this won the chinese contest in gamemaps.com