I know you can visit some theme parks at certain times of year to avoid many children, however what I mean are theme parks built more for imaginative and fun-loving adults.
Take some of the park rides you might find in family theme parks that appeal to both adults and children, but instead of avoiding elements that may confuse/frighten children, they’re allowed to get more detailed or whatever may be more fun for people. Fwiw I’m aware of some smaller scale themed venues (particularly some horror-related ones), but I feel like I’m blanking on any obvious larger scale ones.
Worlds of Fun here in KC does this too. Kids can enter, but the do not recommend they stay after dark. They have a parade, have entire areas that are outdoor haunted houses, and send people running through the crowd to scare them. It is a lot of fun. Most of these regional parks are all owned by the same company (Six Flags, IIRC).