There are four.
Gray Slime - presents an acid hazard when exposed to light
Rot Grub - left behind when a rot grub swarm is killed, can infest a new host, ultimately leading to a new rot grub swarm
Bone Fungus - grows on bones, indistinguishable from bones, creates spore cloud inhaled poison when disturbed, possesses other interesting characteristics
Anchor Mists - violet vapour that inhibits any form of planar travel
There are also thirteen pages of traps, from the new encounter traps, to new standard traps. Psionic traps get some coverage.