1e on my mind... sell me on neat books I can use with it...

I've been running a BFRPG game for a few months now, and recently decided to dig out all my old AD&D 1e books to add some content to the game. Now I'm thinking about starting up an AD&D 1e game later this summer with some pals.

Because of that, I splurged and picked up a ton of second-party OSR books during Lulu's last sale. Now I'm wondering if there are any other great books out there I should know about, and consider picking up at some point. Here's what I just got:

Old School Adventures™ Accessory CC1: Creature Compendium
d30 DM Companion
d30 Sandbox Companion
Petty Gods: Revised & Expanded Edition (Casewrap Hardback)
First Edition Fantasy: OSRIC Unearthed
Monsters of Myth
OSRIC 2.2 (HC)
First Edition Fantasy: Dungeon Hazards
Malevolent and Benign: A First Edition Bestiary
The Wilderness Alphabet (paperback)

And then I've got all the old TSR hardcovers, plus Battlesystem, the two Books of Lairs, and some other assorted doodads.

I'm not really interested in adventures, but any other cool sourcebooks, I'd love to hear about them. Thanks!

1e on my mind... sell me on neat books I can use with it...