From publisher blurb:
This file features seven terrifying creatures for your 5e horror campaign. Within these pages are three iconic snakes and four dreadful spiders:
Snakes: Cobras, Mambas, and Rattlesnakes are among the most venomous snakes in our world. Their venom is far worse than the 2d4 damage of typical poisonous snakes found in the Core Rules. Each of these snakes also includes a short list of other snake that carry similar venom.
Spiders: Peacock spiders, Tarantulas, Trapdoor Spiders, and Wolf Spiders are all different types of hunting spiders. Unlike the spiders in the core rules which build webs and ensnare prey, these spiders either stalk prey like a predator, or wait in ambush. They leap upon prey from great distances, grappling their hapless victims and dragging them back to their lair.
This file also features some other interesting and disturbing options for these creatures, such as two-headed snakes, spitting snakes, and spiders that walk on water, and spiders that hurl spear-like weapons.