Here are the ones I actually use.
w https://www.google.com/search?&q=site%3Awikipedia.org+%s&btn... first result from wikipedia
h https://www.google.ca/search?q=site%3Anews.ycombinator.com+%...
r https://www.google.ca/search?q=site%3Areddit.com+%s reddit
y https://www.youtube.com/results?search_query=%s youtube
m https://www.google.ca/maps/search/%s google maps
b https://builtwith.com/?q=%s add "b " to a url to find out what tech is being used
wo https://www.wolframalpha.com/input/?i=%s wolfram alpha
i https://www.google.com/search?tbm=isch&q=%s google image search
g https://github.com/%s "g upspin/upspin" to jump to https://github.com/upspin/upspin.git
br https://github.com/Homebrew/homebrew-core/blob/master/Formul... read homebrew formula
Re:DuckDuckGo vs Google
by forapurpose on Thursday September 21, 2017 @12:28AM
(#15300595)
That also works with bookmark keywords in Firefox. The setting is in each bookmark's properties; it takes variables (I leave it to the reader to look up the syntax).
Now if I type "h my-search" into the omnibar, it goes to google.com/search?q=site%3Anews.ycombinator.com+my-search which gives me only Google search results from HN.
This is using google's algorithm (not the search bar built into whichever website like DDG) which is still the best, especially if you constrain it to one domain name. I also don't have to type the "!"
The prefix messes up google's text prediction. I guess no one from the chromium team is using this feature, since it would be trivial to fix.