This is basically an updated version of the earlier post from March 2012.
I haven’t searched for new PDFs, but I did wind up adding a few related to comics due to the way a certain site presented them.
Unlike the original one, I’ve alphabetized this list (although it might seem idiosyncratic due to collection sites) by publication title.
Note that some of these will be scans of zines once in print — that’s history! All of these are legitimately free. No piracy. And all of these links lead to a website where you will find the download link. Direct-download links tend to mess people up.