Best one I've found.

Just Sooooo Goooddd...

must have add-on

I am loving this extension! Just wondering if you could add a user page or something where users can submit more examples (If something like this already exists, please let me know!)? A couple of things I'm looking for but haven't figured out just yet are how to have the selected text's hyperlinked url open as cached link [basically launch url as a google webcache search] or similarly open link as viewsource. Hope that somehow makes sense.
Here's some dumb ones I use regularly, lol, if anyone cares. :D

Audible:
https://www.audible.com/search?keywords={searchTerms}
Goodreads:
https://www.goodreads.com/search?utf8=%E2%9C%93&query={searchTerms}
Google Dictionary:
https://www.google.com/search?hl=en&q=define%20{searchTerms}
Google Playstore:
https://play.google.com/store/search?q={searchTerms}&c=apps
Google Site:
https://www.google.com/search?q={searchTerms}%20site:{hostname}
Google Images:
https://www.google.com/search?tbm=isch&q={searchTerms}&tbs=imgo:1
DuckDuckGo:
https://duckduckgo.com/?q={searchTerms}&kae=d&kl=us-en&kad=en_US&kp=-2&kz=-1&kn=1&k1=-1&kaj=u&kam=google-maps&kv=l&kak=-1&kax=-1&kaq=-1&kap=-1&kao=-1&kac=-1&ks=l&kw=w&km=m&k5=1&kt=c
DuckDuckGo Images:
https://duckduckgo.com/?q={searchTerms}&kp=-2&kaj=u&kam=google-maps&kau=-1&kao=-1&kaq=-1&kap=-1&kax=-1&ks=l&kw=w&kae=d&k5=-1&kav=1&t=h_&iax=images&ia=images

In any event, the app is awesome. Highly recommend!

非常好用，自定義常用搜尋引擎後，省掉不少時間

Last thing you need to ad: the possibility to disable the plug-in from a personal list of websites!

Hope author build-in the (https://www.google.com/search?q={searchTerms} site:{hostname})
It's cool, but many people dont's know this. we don't need install addition addon like "Search Site WE"any more.
此扩展可以搜索当前网站,添加 https://www.google.com/search?q={searchTerms} site:{hostname}
这样就不用安装 Search Site WE这样的扩展的.

It simply wasn't quite what I was looking for. The popup was a bit annoying and in the way (and I didn't want it to show up just for highlighting text) and the context menu was inconvenient since you had to go through two menus to use it.
I was looking for something that added a quick-search option to the right-click context menu as far up as possible.
I can say that the plugin looks well designed, though, but it just didn't have the features I wanted :)

удобная вещь

i like this.. but i have a small problem with it.
after the change and customize the setting and restart the browser all the change reset... its my problem or your extension?

The add-on is fantastic! Unfortunately I am too stupid to add Amazon, ebay, google maps and other sites to the search links. I just do not know how to find the right addresses (url). Unfortunately, Google could not help me either ;)
Could this be added as an answer to my rating or can someone specify the url in their own review ... or is there a website where I can find them? Thank you