What system neutral GM aids you keep in your toolbox, to help you craft your games and worlds? Do you have any that you find yourself coming back to time and again?
Though not technically 100% system neutral, the GURPS Mysteries book has so much advice for running mystery/investigation games, I’ve found it helpful to read and skim periodically as most of my games involve some of these aspects.
I have a couple of entertaining random roll books I’ll check every now and then if I want something unusual or unpredictable tossed in. Encounters, treasures, motivations, etc. (‘Roll XX’, and ‘The Starship from Hell’)
I also like incorporating the concept of primal magic from the Primal Order books by Wizards of the Coast (before they acquired D&D or published M:tG.) It’s a capstone system with conversions for the major games of the time. It was a way to give deity level creatures a real boost, magic-wise. It also provided guidelines for building pantheons with several interesting examples, and ways that mortals might acquire Primal Magic. (It also includes a bestiary book, although you wouldn’t want groups of less than 20th level or so to meet the weakest of them.)
Stealing Cthulhu, one of my faves, was mentioned. Surprised no one mentioned Vornheim, which is a table-ready aid that I carry with me in my gaming bag all the time. Create cities on the fly with zero prep. Seriously, zero prep. I also like (and use) other random-generators at the table: Yoon Suin, various tables from Metal Gods of Ur Hadad, Fever-Dreaming Marlinko, etc.
But most of my inspiration comes from Discover Magazine, To The Best of Our Knowledge, Stuff to Blow Your Mind, and a bevy of non-fiction and fiction that I read. I’m not much of a TV or movie watcher. Or, rather, my TV and movie watching is, frankly, hard to gamify: Twilight Zone (the original series), movies by David Lynch and The Brother’s Quay - I try to integrate elements of these into my games, but have yet to be able to fully immerse a game in these weird spaces, though I did come close with a Call of Cthulhu scenario I based on David Lynch’s short film “Rabbits”.
What I wouldn’t give to run or play in a session of Eraserhead . . .
When I was running my 7th Sea Game, I would look up names in the back of the D&D Xanathar’s Guide all the time. I hardly ever use it for D&D, because I can make up fake fantasy names all day long, but in 7th Sea, it felt really wrong to wing out a name like “Xarlothan,” so having the list of names by culture in there was really handy.
Not system neutral but I consider it Vanilla Fantasy - Rules Cyclopedia. The charts, equipment lists, magical items, treasure, etc are my go to references. It was my first D&D book so it has soft spot for me but is also a good tool imo.
Here’s an interesting one, aimed at writers of fiction but still very useful for gaming
The author is a friend of mine and organises a local ‘Fantasy and Sci Fi’ convention. I’m hoping this year we’ll get her to sit down and roll some dice with us.