Omnikey is a very useful Safari extension that allows searching user-selected webpages by entering user-selectable keys preceding the search term. For example, entering "w Los Angeles" in the Safari address bar on my computer and pressing return opens a new Safari window in Wikipedia that's searching for "Los Angeles." This is both easier and faster than navigating to the page you wish to search, entering the search term, then hitting return.
Here's a screenshot of the searches I've added to Safari on my Macs:
Unfortunately, Omnikey doesn't work with Safari 13.
Omnikey is very useful. Are there any other Safari extensions that provide the same functionality?