Monsters by Location and Tier

Tier 0
Bird (Beast), not underground
Commoner (Sentient)
Tier 1
Combatant (Sentient)
Combatant Leader (Sentient)
Insect Swarm (Beast)
Insect, Giant (Beast)
Insect, Dire (Beast)
Mind Eater Host (Monstrosity)
Mind Eater Queen Host (Monstrosity)
Tier 5
Behemoth (Monstrosity, not air or underground)

Tier 0
Monkey (Beast)
Snake (Beast)
Tier 1
Bear (Beast)
Fly Trap, Dire (Beast)
Snake, Giant (Beast)
Snake, Dire (Beast)
Spider, Giant (Beast)
Spider, Dire (Beast)
Wolf (Beast)
Wolf, Giant (Beast)
Wolf, Dire (Beast)
Tier 2
Cockatrice (Monstrosity)
Gorgon (Monstrosity)
Tier 3
Basilisk (Monstrosity)
Chimera (Monstrosity)
Tier 4
Felisphinx (Monstrosity)
Sentisphinx (Monstrosity)

Tier 0
Crab (Beast)
Fish (Beast)
Octopus (Beast)
Piranha (Beast)
Tier 1
Crab, Giant (Beast)
Crab, Dire (Beast)
Octopus, Giant (Beast)
Octopus, Dire (Beast)
Piranha Swarm (Beast)
Sahuagin Scout (Monstrosity)
Sahuagin Warrior (Monstrosity)
Shark (Beast)
Shark, Giant (Beast)
Tier 2
Sahuagin Warchief (Monstrosity)
Shark, Dire (Beast)

Tier 0
Fish (Beast)
Fly Trap, Dire (Beast)
Mind Eater (Monstrosity)
Monkey (Beast)
Octopus (Beast)
Piranha (Beast)
Snake (Beast)
Tier 1
Bog Crawler (Monstrosity)
Octopus, Giant (Beast)
Octopus, Dire (Beast)
Piranha Swarm (Beast)
Sahuagin Scout (Monstrosity)
Sahuagin Warrior (Monstrosity)
Snake, Giant (Beast)
Snake, Dire (Beast)
Spider, Giant (Beast)
Spider, Dire (Beast)
Swamp Spitter (Monstrosity)
Mature Swamp Spitter (Monstrosity)
Tier 2
Sahuagin Warchief (Monstrosity)
Tier 4
Sentisphinx (Monstrosity)