LSD Dream Emula... oh wait, you already mentioned it!
Well, right now I'm playing Super Galdelic Hour for PS2. It's certainly conceptually bizarre and something that would never appear on PlayStation today. Fanservice aside, I like the weirdness, the funky take on futurism (like Space Channel 5 in some ways), and how the graphics look impressive for PS2 standards:
When I want surreal or bizarre games, I learn about them mainly from Alpha Beta Gamer. For something for something along the lines of "this game shouldn't exist", there's Kotel ne Gori:
And for something unsettling, there are games like those by Yames, including Growing My Grandpa: