Though location specific, the Wanderers Guide books from Goodman (Monsters of the Endless Dark, Monsters of the Boundless Blue, Primeval Groves) and 3 AM Games (Monsters of the Savage Snow) are another good series, though the OGC is just the stats and combat section. And I suggest staying away from PG- the unedited version was printed. It is still good for ideas, but it would take a lot of effort even with the errata to clean up the monsters.
