Most of this beyond the Burroughs and Lovecraft has been collected in the last two years, sometimes in and out of small book stores found while on camping trips, starting back in the run-up to the Beta release of DCC RPG. Most of the second image I haven't yet read. I'm part way through the Shadow Kingdoms collection, and almost done with Eyes.
Somehow I left out the Face In The Frost from both pictures; and A Princess of Mars is missing since it is on my son's reading stack, and I forgot to grab it.
I know there are a few other Appendix N books I've read over the years, but can't remember which titles/authors to speak of...
Of course, the book in the lower corner isn't Appendix N -- just a cool find while searching for App N books!