I often do searches with multiple search engines and extras with the same query but with site:reddit.com added at the end. Being able to press CMD L to focus the URL bar, and then CMD C with all the text selected would make things a lot faster. This was added months ago to Firefox but it looks like it was removed now.
You can add @Google, @Wikipedia or something else at the begging to do so, alongside with setting custom shortcuts and extensions to support searching on other sites, like Genius (music lyrics and interpretations)