The hymenogastraceae family of fungi contains around 1,600 species of false-truffles and agaric mushrooms. Modern-day molecular testing allowed for the inclusion of agaric mushrooms. Before genetic testing, the family only consisted of false-truffles. Many hallucinogenic mushrooms belong to this family in the genus Psilocybe.
An infamous hymenogastraceae mushroom is the "Deadly Galerina" Galerina marginata. Its amatoxin, alpha-amanitin, is one of the most deadly. Usually resulting in death in 7 days because of severe liver damage and kidney failure. It is highly recommended you learn how to identify this mushroom, as it is common with many edible look-alikes.
Genera of Hymenogastraceae