Horror Genres 
Body Horror/Biological Horror - Horror that portrays visceral violations of the human body or in some cases, other living beings including mutation, mutilation, disease zombification and the body's general limits and capabilities.
Comedy Horror - Horror combined with comedy, typically in a sattirical or parody manner.
Giallo - Italian subgenre of horror-thriller films characterized by a blend of murder mysteries, psychological horror, eroticism, and stylized violence.
Slasher Horror - A movie with a plot revolving around a killer/killers typically with a non-firearm weapon who may also stalk or chase the protagonist(s).
Horror Tropes 
Backing into the Danger - When a character walks backwards and steps into/bumps into the danger or antagonist.
Creepy Children - When a child/children do something creepy or unsettling, mismatching the demeanor of a child.
Final Girl - When the last survivor is a woman or most commonly, the main woman protagonist.
Key Fumble - When a character urgently needs in/out of a location and fumbles with or drops their keys to build tension.
Lewton Bus - A jumpscare thats harmless, like a scene that builds tension and ends with a jumpscare of something that isn't the antagonist.
"The Call is Coming from Inside the House" - When the antagonist is calling the protagonist from inside their house or location.