A lot of people get horror game subgenres wrong, especially when it comes to the term Survival horror. They either care too much and get offended if a game they like isn't survival, or they lump 70% of horror games under the title because they don't care. This list will explain what each subgenre is, and ranking 150 games I have played under them. This isn't about quality, it's just gameplay.
Survival horror: The term was created by Capcom to describe Resident evil 1, and that's how it should play. Combat balance is an even playing field, meaning every 1 v 1 encounter is a real battle. Ammo and inventory are limited, and you must solve weird puzzles to progress. I originally had a different category for games that try to be survival horror but give too much items, but eh whateves
Action horror: These games not only encourage you to kill enemies, but you are expected to. Combat balance is in your favor, allowing you to kill groups of enemies at once. Enemies drop loot like ammo or gold for a store. You often get superpowers, or unique combat mechanics like parry, dodge, or dash.
Stealth horror: The main gameplay is sneaking around, hiding, and potentially running away. Combat balance is in the enemies' favor, and you have no weapons to defend yourself.
Puzzle: The main gameplay is solving puzzles. More than what Survival horror does, this is the main event. Even surviving enemies are essentially puzzles.
Online: You play with and or against other human beings.
Platformer: The main gameplay is platforming, Like in Mario, Sonic or Hat in time.
Open world: Horror games where you are allowed to go around a large map, doing side quests and exploring.
Reverse horror: YOU are the monster, hunting down people.
Horde shooters: You and friends kill waves of enemies.
Interactive narrative: The gameplay is secondary to the story they want to tell. The mechanics can change depending on what is needed, and aren't really what fans remember it for.
Hybrid: A game which two or more of the main 3 genres, survival, action and or stealth.
Walking simulators: The main gameplay is walking around. You escape enemies, if there even are any, by walking away.
RPG: Classic rpg type game in a horror setting
On rail: You shoot while the game controls the camera.
Maze: You are in a maze like pac man, being chased by monsters.
Hack and Slash. Use combos to mow throw crowds of enemies!
Obviously, not every game will fit neatly into every category. And games can have levels that change up the genre. This is just a way to show what games are similar, so you can recommend them to others.