A while back there was a thing floating around about the ten gaming books you'd most like to have if you could only have ten. I recently did some gaming/camping (my favorite kind of camping involves gaming and my favorite kind of gaming involves camping) so I got to actually make this decision. I didn't need ten. We brought:
Moldvay/Cook B/X.
tucked into Moldvay Basic was
this. It came in handy.
That's two.
We also brought:
Raggi's
Random Esoteric Creature Generator.
The 1e DMG, but mostly because since we were camping I thought it might be useful to have something hard to write on.
We brought this:
Everything in this I either made or found on the internet! Here's a breakdown of the indispensable dungeon master tools in here:
Pages 1 & 2:
megadungeon missions
random swords and sorcery name generator
movement, encumbrance, light & vision, reaction roll chart, foraging & hunting, xp
Pages 3 & 4:
the Ravaged Ruins charts from
Wilderlands of High Fantasy (worth three bucks for these two pages alone)
Pages 5 & 6:
MegaDungeon Area Name Generator
MegaDungeon - Doors
Page 7 & 8:
the
Dismal Depths Trap Tables
random rooms and d100 things in a pit from
here
Pages 9 & 10:
Pages e11 & 12:
Trick effects and "big ol' list of tricks from C
Pages 13 & 14:
Wilderness and dungeon wandering monster tables
Pages 15 & 16:
Creepy combat commentary and "what are the monsters doing" from Telecanter
and a list of Shakesperian insults, just in case!
pages 17 & 18:
Pages 19 & 20
My treasure hoards, looting and random magic item charts.
pages 21 & 22:
We also had my Arcane Stress and Spell Mutations (which got used by the DM, there were no M-U PCs. There was an Elf, but he got taken out by a black pudding before he got to cast any spells) and my critical injury table.
I buy gaming books, adventures etc. but I sure don't need to.