I make great use of DuckDuckGo's bang feature, with which you can change your search target by typing
<search term> !<bang code>, where
bang code is any of the defined codes. For example, I saw a map just now of a place called 'Erdalen' and didn't know where it was, so I pressed
ctrl-L to enter Firefox's address/search bar, and typed
!osm erdalen and it took me straight to this place south of Bergen in Norway.
Other bangs that I use a lot along with
!w for Wikipedia,
!wd for Wikidata, and
!r for Reddit.