For me "dark" fantasy aka "grimdark" is about darker themes, harsher language, and more realistic depictions of awful situations being in the forefront of what is happening (as opposed to just existing in the background). The book should be gritty and grim and feel hopeless and even victories should pyrrhic most of the time.
Fantasy General
I love that idea if pyrrhic victories. I've been asking around about what are some favorites in this "genre" and have been suggested: The Witcher, First Law, Goblin slayer, Embers of Illenial/Mageborn. What else should I add to this reading list?
I've definitely heard First Law is both grimdark and good. I have it on my TBR.
if you're not opposed to REALLY dark, Mark Lawrence's Broken Empire trilogy (starts with Prince of Thorns) is very good. You kinda have to push through hating theMC for the first part of the first book but it's totally worth it.
Also the Poppy War trilogy by RF Kuang is excellent.
Also, I will never pass up the chance to recommend Malazan Book of the Fallen.
Love this. Thank you.
So I come upon the definition that Grim Dark is the opposite of Tolkien-like fantasy.
Any works that subvert the Tolkienesque tropes qualify as Dark Fantasy. For Example Salvatore's Jarlaxle & Entreri Trilogy, A.S Etaski's books (very sexually explicit), Some of the Star Wars Legends books in the Vong series. Etcetera
As far as GrimDark notable books, all those listed are fantastic. However imho y'all forgot about GRRM's ASoFaI (Game of Thrones& Sequels).