Top 3 All-Time RPG Supplements

[GM Lent]

The products that have seen the most use in my D&D games over years are

1. Secrets of the Lamp by Wolfgang Baur
2. The Illithiad by Bruce Cordel
3. Dragon Kings by Timothy Brown

 

[John R Davis]

1. Pellinore from Imagine magazine.
2. City System for AD&D.
3. Starstone by Northern Sages

 

[CleverNickName]

My Top 3:

1. Module X1, "The Isle of Dread."
2. AC9, "Creature Catalog"
3. Module X4, "Master of the Desert Nomads"

I've adapted these books to every D&D edition that I've played through the years, whole or in part. They are that good.

 

[R_J_K75]

2. City System for AD&D.

Definitely a good one, Cities of mystery was good too. Great tables for random street scenes.

 

[Lord Mhoram]

Not sure about all three - but this one has to be among them. It was a sourcebook for Champions, that from a gameplay side had a huge number of characters heroes and villains for a GM to use. But it is also one of the greatest game authors chronicling his campaign. It is also one of the best GM advice books ever written - there are a lot of thing in there that are standard now, but when this was published it was groundbreaking - I'm speaking of course of Aaron Allston's Strike Force (the original)

 

[Geekrampage]

For my group:
Street Fighter Player's Guide for Street Fighter the STG.
Ultimate Powers Book for Marvel Super Heroes, which we played a LOT in high school.
Central Casting, Heroes of Legend which we used for AD&D, 1st and 2nd ed.

Honorable mention goes to Mekton Zeta Plus for Mekton Zeta, but I spent more time making robots than actually playing that game.

 

[Celebrim]

3e Player's Handbook, WotC
1e AD&D Dungeon Masters Guide, TSR
Book of the Righteous, Green Ronin

 

[overgeeked]

I can’t do three, so here’s five.

X-Treme Dungeon Mastery, by Tracy Hickman.

Return of the Lazy Dungeon Master, by Mike Shea aka Sly Flourish.

Creative Campaigning, by TSR.

Campaign Sourcebook and Catacomb Guide, by TSR.

Dark Sun Campaign Setting, by TSR.

 

[Umbran]

Caverns of Thracia by Paul Jaquays.

Mod Note:
Her name is Jennell Jaquays. It is considered rude to use the prior name, so please don't.

 

[Yora]

The d6 Star Wars Gamemaster Handbook - The only GM book that teaches how you run games.
D&D 3rd Edition Monsters of Faerûn - Small book, but lots of my favorite D&D monsters of all time.
D&D 3rd Edition Manual of the Planes - I just think it's neat.