All I know of is...
Gog: They have games that are compatible with free engines and
reimplementations of free engines. They also have DRM-free documentaries.
Humble Book Bundle: They have two book bundles right now, Peanuts and Make.
Comixology: They have a selection of DRM-free Comics, but they make it really
inconvenient to filter out DRM's comics and even the URL I have that says it
DRM-free is still missing DRM-free Comics. Most (if not all) Archie Comics
along with the Walking Dead are DRM-free and you can which one is DRM-free by
the download icon in the store page of the Comic.
https://www.comixology.com/DRM-Free-Comics/page/2794
Anybody that sells MP3s: The late Steve Jobs did at least one thing we all
can admire, he used his Conman powers for good instead of evil. He made all
of the big music publisher agree to a change in the terms of the contract
making the EULA more restrictive making it allowed to run on fewer devices of
which the money hoarders in the suits loves, but they didn't read the the
part that says "all music will be DRM-free" so the EULA didn't matter. Too
bad his trick didn't work a second time with Movies :(
