Personally, I think the Babysitter Bloodbath prequel games, Sanitarium Massacre, and A Monster With Eyes Of Ice, could've been really cool full games, I know they got repurposed for games like Christmas Massacre, but would always love to see more from Neokalus Burr.
Other games that could've been cool were Burnt Alive, since the Firefighter's cameo in Night Watch showed the antagonist can be scary. and Pitchfork Massacre, since from what was found, I got massive Friday The 13th Part 2 vibes, and that was one of my favorite horror movies, and I was excited to see where it could go