Appendix N was a list of suggested reading in the AD&D Dungeon Master's Guide. Its Gary Gygax's list of stories, novels, and authors that inspired Dungeons and Dragons.
Its interesting that overall its much more Sword and Sorcery than high fantasy, more pulp than epic, more Conan than Lord of the Rings. Gygax claimed that he only pushed so many Tolkien elements into the game to appeal to a larger fan base. That's arguable, its also possible he was bitter at Tolkien's estate for making him change names (Ent to treant, hobbit to halfling, Balrog to Balor, etc.). Regardless, there's a LOT more going on in D&D than just Lord of the Rings ripoffs.
Appendix N is the inspiration for Dungeon Crawl Classics, an attempt to put more weirdness into fantasy. As someone who likes D&D but is sick of a lot of the tropes, this appeals to me.
Anyway, there's this awesome series on Tor.com where two guys are reading and commenting on authors from Appendix N: Advanced Readings in Dungeons & Dragons. There's some really interesting analysis on what parts of these stories made it into D&D, both from Gygax's direct influence and their impression on players as the game grew.
Related there's an article about Orcs that touches on some thoughts about racism in Tolkien that have been bumping around in my head (short version: its complicated, and I think its in the spirit of the author to talk about it).