Many varieties of non-sentient monsters populate Liathen.  Below is a list of some that have been encountered:

Spitters -- exist in several varieties, created by Marist from souls of the evil.  When they die, they leave a foul residue behind that prevents plants from growing.

Wolves

Hippopatamus -- in the orc lands

Manticore -- live in caves, forests

Owlbear

Giant Spiders -- tamed by goblins, possibly using divine magic

Dire Frogs -- live in swamps in the Tanglewood Forest

Dire Lions -- used as mounts in the orc lands

Drakes (or wyverns or psuedodragons or something?) -- appeared in Rowling ~125 years ago, causing much damage