It's great to see that this thread is useful for others
Couple of titles that people may want to give a try if they've enjoyed Ice-Pick's previous work. Some are going to be well known, some not.
If you enjoyed the atmosphere and need to survive of Pathologic you may want to take a look at The Last of Us, How to Survive and Under the Garden. I Am Alive is also worth a look.
Like the surreal vibrancy and identifying soundtrack of Cargo! ? You may want to give Contrast a go. For a solid experience with a surreal and interesting atmosphere there is Alice Madness Returns.
For The Void fans there is always Planescape Torment and Mike Inel's "Which".
I haven't had enough time with Knock-knock yet to have comparably titles come to mind.
Unrelated to Ice-Pick but still for various reasons worth having a look at are Shadows of the Damned (A deliriously silly B-Movie in video game form) Hatsune Miku Project Diva F - a fun and vibrant rhythm game that is simply eager to be played. Aquanox 2 is something of an oddity. An underwater action/sim game that offers an interesting experience.
Plus there's no harm in showing mods some love. Any fans of Doom might be interested to know that "Brutal Doom" V19 has been released and is only getting more and more ridiculous.