This is not revolutionary but it saves some keystrokes when wanting to limit results to certain sites.
Personally I don’t really limit anything with Kagi. It’s usually just finding what I want without having to do anything.
A bit of a hot take. The only real difference between Lemmy and Mastodon is sorting of the posts, everything else is UI. You can have Mastodon experience very similar to Lemmy although it breaks a bit with high traffic. It’s actually quite useful to subscribe to low traffic text based Lemmy communities via Mastodon because new comments bump old threads and it’s kinda like old forums, especially in a client with threaded view.