On DDG those words with the exclamation point are called !bangs, and you can search them by adding !bang to the search query. If you only put “!bang” without a query it takes to the landing page.
For other operators you’ll have to look at each search engine’s help pages.
Is there a site that lists all the keycuts (like keywords and shortcuts in 1) for such search engines?
Like
!for DDG and
site:textfor Google
I do know that Qwant at least does support the latter, sort of.
On DDG those words with the exclamation point are called !bangs, and you can search them by adding !bang to the search query. If you only put “!bang” without a query it takes to the landing page.
For other operators you’ll have to look at each search engine’s help pages.