From publisher blurb:
It has been over 20 years since Necromancer Games first unleashed the Tome of Horrors, and our philosophy has not changed... everybody needs more monsters! Necromancer Games has always been known for its monsters, and with the Tome of Essential Horrors, we would like to introduce those unique and mysterious creatures to your Old-School Essentials table.
This beast of a book contains over 100 monsters and brings classic monsters from Frog God Games and Necromancer Games to OSE referees and players. Each entry includes a full OSE stat block, classic black-and-white art, and an interesting encounter that highlights the creature.
The Tome of Essential Horrors contains all you need to gleefully exceed your players' expectations. Can the heroes escape the clutches of the witch tree, the riptide horror, or the cave fisher? Will they survive the pyrolisk’s conflagration gaze? We cannot guarantee a TPK every time, but you’ll have buckets of fun trying!