Yes, no ads.
From any time period. With a couple very narrow exceptions.
A friend of mine got an old magazine from the 1890's return to sender for extra postage because of ads.
In addition to stuff like books and magazines without ads. (Magazines without ads?! Don't think I've ever seen one) 8, 9.5 and 16 mm film is also ok to ship media mail 35mm movie film is not. Probably because it's mostly a commercial product.
Beta, VHS, reel to reel tapes, 8 tracks, cassettes, records, computer disks.....all ok as long as there's no advertising.
http://about.usps.com/notices/not121/not121.htm
The wording used to be different, allowing unbound printed matter, and I used to ship bulk lots of cheap card that way until they decided it wouldn't be allowed.
The actual regs here.
http://pe.usps.gov/Archive/PDF/DMMAr...050106/173.pdf
Steve B