Last updated on December 10th, 2021
It looks like Archie Comics is the latest major publisher to become DRM-free on Comixology.
I say “latest” since this change happened back in October, but has gone largely little-publicized outside of Comixology’s own Tumblr page. (Smaller publisher “Alternative Comics” is also now DRM-free.) Comixology’s site also doesn’t list Archie in the list of DRM-free publishers, but looking through the various books, they’re all complete with the download/archive icon:

Checking the “My Backups” section, all of my previous Archie comic purchases are also all available for downloading as PDFs or CBZs. (I prefer CBZ as a comic format.)
Given Archie’s one of the more prominent secondary comic companies, this is quite welcome news. With Archie on board, the remaining major monthly comic publishers that aren’t DRM-free include: DC; Marvel; Dark Horse; Boom! Studios; Avatar Press; Zenescope; Viz (though their yaoi (“boy’s love”) subsidiary “Sublime” is sold as DRM-free PDFs); and part of Archaia’s line (some of it’s available DRM-free via DriveThruComics.com, but not all of it). Hopefully these publishers will join the rest in becoming DRM-free. Of course, I expect DC and Marvel to be either the final two holdouts or never going DRM-free, given their parent companies’ DRM-obsessed natures.