Just announced via the DCC RPG Google+ Community is Crawling Under a Broken Moon for DCC RPG. I have no idea if this is going to be free or cost a few bucks, but given it's Thundarr-esque, hell yes.
Also for DCC RPG is Crawljammer, soon to be in its second issue. A six-issue Print+PDF subscription will set you back $23.
And let's not forget the EXCELLENT MÖAR METALLITUDE of The Metal Gods of Ur-Hadad which is so awesome it hurts just to pronounce its name. Written for
Finally, there's Threshold: The Mystara Magazine, produced by the fans over at The Piazza forums. Each issue is a free PDF and these things are huge; each issue is 150+ pages of Classic D&D Mystara goodness.
Does anyone know of new zines I'm not aware of that need to be added to the zine page?