Barton, William A. Cthulhu By Gaslight: Horror Roleplaying in 1890's England. Oakland, CA: Chaosium, 1986.
A xeroxed reprint appeared in 1989. This is an excellent source for Shadows in the Fog if you can find it, which is not easy.
Bridges, Bill, et al. Mage: The Ascension. Rev. ed. Stone Mountain, GA: White Wolf, 2000.
There are a number of editions, all quite different in various respects. This seems to be the most recent, but we have no particular opinion about quality.
A very interesting take on occult-style magic, where characters have demons that work for them, whose magic is not entirely predictable or tractable.
Ernst, Rick, Shirley Madewell, Chris Pallace, et al. !ConspiracyX. 3d ed. Albany: Eden Studios, 1997.
Pretty cool way of doing the Men in Black sort of thing -- not the comedy, either. Definitely not the comedy. For more occultism in !ConspiracyX, see:
Forsaken Rites.
Gygax, E. Gary. Advanced Dungeons and Dragons. TSR Hobbies, 1980 etc.
Lots of different books, editions, years, revisions, you name it and you know. Don't get us started.
Jonsson, Gunilla, Michael Petersen, Nils Gulliksson, et al. Kult. 2d ed. N.p.: Target Games, 1997.
Extremely atmospheric and creepy, but rather traditional mechanically. A third edition is out, but I haven't seen it. The 2d edition has one great flaw: the typeface requires a magnifying glass, and one gets a headache reading the book. Perhaps that's intentional? For more occult stuff in Kult, see:
Beyond the Boundaries
Heart Mind & Soul
Oracz, Michal. De Profundis: Letters From the Abyss. Trans. Maja Apollonia Pica. London: Hogshead, 2001.
Probably the oddest RPG text you are ever likely to read. Fascinating reflexive weirdness, where the game is the horror. Really, really clever.
Petersen, Sandy. Call of Cthulhu. Chaosium. Several editions.
If you don't know the game, you need to run right out and get it. One of the greatest RPGs ever written.
Snead, John R, with Heather McKinnery and Sam Shirley. Liber Ka: Authentic Western Ceremonial Sorcery for the Nephilim Roleplaying Game. Oakland, CA: Chaosium, 1997.
Quite useful in its way for Western sorcery in an RPG context, but a little mechanical.
Sorensen, Jared. !InSpectres. MementoMori Theatricks: http://mementomori.com, 2001. In edition 2.04 as of 1/19/03.
A fascinating narrativist sort of game in which the PCs have a franchise in a sort of Ghostbuster firm. We lifted the Confessional (here called Commenting) from InSpectres.