In the tradition of the 1st Edition Dungeon Master's Guide, the list below is intended to showcase artwork that captures the overall feel and inspiration for the setting. Direct links to the artists are provided, and no infringement on rights is intended. Please let me know if a link is broken.
The first D&D artist that truly captivated me.
He has a massive breadth of work on his website, but the Planescape stuff is absurd and beautiful.
Mirror Reaper is an album that absolutely rips. It is played regularly during sessions.
The king of procedurally generated settings.
Biggest takeaway from playing this was not 'pre-planning' anything. Emergent stories happen through play.
Here it is, if you aren't familiar.
Probably obvious. Play it.
I haven't played many Souls-like games, but this one struck a chord and was definitely something that helped formulate a lot of the campaign procedures.
So many parts of this game are incredible - the music, gameplay, art design are all first class.
Mostly, this game inspires what the world 'looks like' in my minds eye. It's clearly post-apocalyptic, but the history isn't completely clear. The mix of sci-fi and fantasy elements is well done as well, and creates a truly unique aesthetic.
Available on a ton of different platforms.
Definitely mined this game for general atmosphere, monster ideas, and some ideas for crafting mechanics.
Details here.
Between Aleister Crowley's weirdness and occult history, and the pseudo art-deco drawings, these cards are quite evocative.
Linking to wikipedia because so many general tarot sites are lame.
The first of many 'post-OSR' publications that sparked my interest in minimal RPGs with traditional sensibilities back in 2012. The campaign would not exist in its current form without this game.
The new edition is an absolute delight.
This is an awesome tabletop game and miniatures magazine that is still pretty new to me. Super inspirational stuff, all around.
Link to their main page here.
Only read the first half of the series many years ago. The primary influence here is a setting/situation that reveals itself over time. And all of the wild genre-crossover.
Reference here.
Unspeakable, eldritch horror. One of the kings of pulp sci-fi fantasy.
The most influential are the short stories involving the Dreamlands.
A 'monster manual' with no mechanics at all. This book is a masterclass in gameable creatures to introduce to your game, despite not having a stat block.
Available here.
Scrap Princess' illustrations have informed my own sketches, and their work adorns the walls of the campaign's gaming space.