It seems that you're using an outdated browser. Some things may not work as they should (or don't work at all).
We suggest you upgrade newer and better browser like: Chrome, Firefox, Internet Explorer or Opera

is there another source like the steam workshop? I am looking for new blueprints, mods, maps etc. for this awesome game!
Workshop is by far the biggest one (simply because the majority of players are on Steam already anyways), but there's also this:;cat=174

And one of the more active modders has his own site: