One source might be, of all places, Magic cards. There were a few series - Zendikar might have been one - that had a lot of surrealist landscapes in their art - chunks of land floating in the air, that sort of thing.I always wanted to base a campaign world around surrealist landscapes, but I haven't found very many pictures to use that didn't include blatant references to technology, so I haven't gone further with the idea.
Dreamlands-type locales are fitting, too, i think.Surrealism works if one has the party in an Alice-In-Wonderland type of setting or adventure (I tried this once for a gonzo one-off and it worked well enough), and-or if a party somehow finds its way to the Plane of Chaos, at which point anything goes.
You might try one of those recent txt2img generators, using the keyword "surrealism" in the prompt.I always wanted to base a campaign world around surrealist landscapes, but I haven't found very many pictures to use that didn't include blatant references to technology, so I haven't gone further with the idea.