I have to admit that although I played D&D a lot back in the day that I never really knew about the famous Appendix N. Part of that is we were playing AD&D 2nd edition and part of that is I was always a player in TSR games.
But also I think as responsible nerds we had just accidentally read most of the list. I admit I still have yet to read Margaret St. Clair or Manley Wade Wellman, but we were pretty deep into Leiber, de Camp, Moorcock, Burroughs etc. The one exception from the immediate influences was Jack Vance, whom I’ve only started reading relatively recently. Vance is fucking awesome, but I personally hate how his magic has become codified into spellbooks and daily memorizations. Magic shouldn’t be mundane. Magic shouldn’t’ be math.
Anyway, my guess is that Appendix N is valuable because it was small enough to be manageable, so many people grew up on it, and it wasn’t just a list of best-sellers but had some variety. It’s hard to remember now, but in a pre-Internet era, it wasn’t easy to get recommendations. Now we have too much to read, too many games to play; far too much information at our hands. It’s a nice obstacle to have, but it is (or can often be) a bit of a problem.
So I propose my own supplemental list to Appendix N, consisting of recent books, which I’ll define as having been published in this century. (Which leaves out the area between 1975-2000, which excludes some wonderful authors indeed. I’m also not limiting my list strictly to high fantasy, as I think most RPGS can support the breadth of the speculative fiction milieu.
Disclaimer time. I read a lot, but I’ve never read particularly for this purpose and I’m sure I have a lot of blind spots. If you question an inclusion or exclusion, please let me know in the comments. Like the original Appendix N, this isn’t a comprehensive list but rather a place to discover works you may enjoy. (And unlike Appendix N, this isn’t actually accompanying anything so it’s really a list of books that gamers may enjoy
While Gygax didn’t justify his inclusions, I’ll try to add a sentence fragment to each entry to explain why I included it. There’s no particular order to this list and when I list the first book in series the rest of the books probably get a default recommendation too.
Appendix N Augmentation
The Lies of Locke Lamora by Scott Lynch Lovable rapscallions in fantasy Venice.
Everything by China Mieville, but especially the Bas Lag untrilogy. More ideas in one book than most writers have in a lifetime.
Desert of Souls by Howard Andrew Jones There are others, but for me this is the best medieval Arabian fantasy around today
The Horns of Ruin by Tim Akers Clerics and magic and intrigue and ancient civilizations oh my
The 5th Season by NK Jemisin Her books are all a bit too YA for me, but there is world-building and cool volcano magic aplenty here.
The Last City by Nina D’Aleo How can any gamer resist a book billed as “Bladerunner meets Perdido Street Station”?
The Dervish House by Ian McDonald Nanotech in near-future Istanbul
The Croning by Laird Barron Possibly the best bit of cosmic horror since old HPL himself
Nights of Villjamur by Mark Charan Newton Fantasy world with superheroes…
The Windup Girl by Paolo Bacigalupi Biopunk, Shadowrun-esque with genetically engineered elephants providing energy to the cities
The Road by Cormac McCarthy Bleak, grey, depressing, grey, bleary, grey and so good
Night Watch by Sergei Lukyanenko Cool urban fantasy in Moskva-written in the late 90s but I think not translated into English until the 2000s
Promise of Blood by Brian McClellan Flintlock fantasy–perfect for those RPGs set in 17th century Europe
The Dragon’s Path by Daniel Abraham High fantasy for adults
Red Country by Joe Abercrombie Western Fantasy, two great tastes together at last and in my opinion his finest work
Oryx and Crate by Margaret Atwood Dystopian biopunk starts slowly but is thought-provoking and gameable
The Curse of Chalion by Lois McMaster Bujold All the drama, intrigue, and tension of a fantasy trilogy in one efficient novel
Annihilation by Jeff Vandermeer Pretty much a Trail of Cthulhu campaign in novel form.
Tales of Dunk & Egg by GRR Martin. Cheating because the first one came out in 1998, but these are far more focused and fun than ASoIaF, like Lieber writing in Westeros
Children of Hurin by Prof. Tolkien Ha! Cheating, I know. But seriously read this again. Or better yet, listen to Christopher Lee read it to you
 My high school went to something called block scheduling my senior year and we had a free 1.5 hours every day called Focus. It was meant to be used for studying or homework or some shit, but let’s just say that we played enough D&D that I got my cleric Jorlan to level 20 in Dark Sun. I don’t think I’ve ever even got another character as high as level 5 in any game, ever.
 In case you’re wondering, Hobie ran Star Wars, Earthdawn and Buck Rogers, Wind ran Rifts and Kara-Tur and TMNT and a bunch of other stuff, Oreon ran Werewolf, and I ran Elric. We weren’t cool enough to play MERP with the older kids.
 It was admittedly high school and I still thought David Eddings wrote great dialogue and the Death Gate Cycle was the bomb so I’m not claiming much of anything other than possession of a library card.
 This is beyond the scope of this modest blog post, but writers like Frank Herbert, Ursula K. LeGuin, Tim Powers, Guy Gavriel Kay, Fred Saberhagen, William Gibson, and Steven Brust belong in any discussion of RPG related material. On the other hand, these writers are all highly successful and don’t necessarily need additional attention.
 Although I won’t list books like those of Patrick Rothfuss or Suzanna Clark, for instance. Even though I quite like their stuff, I don’t think they do anything new or interesting enough to warrant inclusion.