Emulate the silent hill games and the resident evil games
Amnesia is easy to run
Undying
The Dark Eye
Eternal Darkness: Sanity's Requiem
Alone in the Dark
Clocktower games
System Shock series
Dark Fall: The Journal
Manhunt 1&2 (get the uncut version of 2)
Realms of the Haunting
Shadow of the Comet
Ripper
Scratches
Seven Games of the Soul
Rhiannon: Curse of the Four Branches
Zork Nemesis
The Lost Crown: A Ghost-Hunting Adventure
Divi-Dead
Sublustrum (Outcry)
Phobos 1953
Anchorhead
The Residents: Bad Day on the Midway
Thief 1/2/Dark Mod (certain fan made missions)
Nosferatu
Resident Evil 1,2 3 and Code Veronica
Sllent Hill 1,2 & 3
Haunting Ground
Siren, Forbidden Siren and Blood Curse
Fatal Frame 1, 2 & 3...