can I use operators with config variables?

[Hifilo]

for example could something like this:

ZSH_THEME_RANDOM_CANDIDATES=!( "imajes" "gozilla" "smt")

be used to load all themes at random except the ones I specify?

[carlosala]

That is not possible in zsh.

[mcornella]

There is no such syntax in zsh but for this specific use case you can use this other variable: ZSH_THEME_RANDOM_IGNORED.