Your Favorite RPG Supplement, for any Game, Period

[Brakkart]

I'd say the book I value highest (and have gotten the most use out of) is my copy of Aurora's Whole Realms Catalog. Perfect for when a party is in a city and wants to know what can be bought and for how much.

 

[Voadam]

I still love reading the Realms of Chaos supplements for WFRP.

I wish I owned these, from what I saw of them they were excellent.

 

[JoeGKushner]

There were numerous generic resoruces that I used when younger.

Lejentia

City Books

Grimtooth's Traps

Aeshiba: Greek Africa

All of the above were used numerous times.

DMG 1: Still use some of the tables to this day.

Delta Green: Mix this and Dark Champions and you're good to go. Adding more Delta Green books and more Dark Champions books only makes things better.

Fantasy Hero for 5th ed is a pretty solid book. I think it even edges out GURPS Fantasy a bit.

Star Hero vs. GURPS Space is another close one, but I'll say Star Hero probably edges out again.

 

[Crothian]

Original Thieves World Box Set
Pulp Hero
Freedom City
Everyday Heroes for Deliria
Dark Ages Fae
And many Gurps books

 

[Gamera]

Nightmares of Mine by Ken Hite. If not the end all it certainly is a be all for understanding and running horror games.


Ditto on anything Delta Green and Unknown Armies for just plain fun reading.

 

[Crothian]

Nightmares of Mine by Ken Hite. If not the end all it certainly is a be all for understanding and running horror games.

I forgot about that, really well done. He updates and includes a lot of that in Gurps Horror.

 

[GMSkarka]

I was going to say the Marvel Superheroes Ultimate Powers Book, but it's already been listed.

So I'll go with my second favorite: Cthulhu by Gaslight -- a brilliant supplement for Victorian-era gaming.

 

[Philotomy Jurament]

DMG 1: Still use some of the tables to this day.

I still use my 1E DMG too (while my 2E DMG does nothing but gather dust). However, I recently picked up Gary Gygax's World Builder, which is big collection of lists and tables similar to those found in the 1E DMG. It's not a how-to, book, but a reference work. If you like the 1E DMG for the colors, herbs, gems, dungeon-dressings, types of rooms, et cetera, then you'll like this book, too.

(Living Fantasy, another book in the series, is pretty cool, too. It's one take on how a magical fantasy society would work.)

 

[Treebore]

Definately got my vote. I love that book with the fire of a thousand suns. And I too use it for all kinds of things; in D&D, in d20 Modern, etc. I used tons of mechanics from it in my homebrew d20 hodge-podge system, and I use CoC creatures all the time.

Not only that, it's a beautiful book, and the Gamemastering advice is some of the best ever written.

This is the closest anyone has ever come to selling me on this, in any edition. In fact, if I find a deal on it I'll be buying it. It will be all your fault!

 

[Treebore]

I can only come down to two, and only if I stick with d20 D&D.

Book of the Righteous (like others I consider this to be THE best work on Religion/clerics/etc..., ever, in any edition)

The Kalamar DM screen (3.5) RAWKS!! I bought 4 of these. I still use it for my C&C game just for the price lists and equipment lists alone. Oh, and the poisons and diseases.