For most of the addons i have tested with similar ones to get best and updated ones only

1.tab image saver -- to save images from right tabs,all tabs,current tab with shortcut

2.Double-click Image Downloader

3.tweaks for youtube -- Over 70 features

4.toolbox for google play store

5.web search navigator -- to navigate in google by shortcuts like up/down to go to next/prev results and left/right to go to next page

6.searchmage -- many options to customize google

7.google images restored

8.google image sizer -- to filter images in google by megapixels

9.undo close tab

10.nextpage by sylecn -- go to next page with press of n

11.reload all tabs in window

12.foxscroller -- autoscroll sites with custom speed in pixels,toggle direction

13.enhancer for youtube

14.hotkeys to switch tabs left and right

15.shortkeys(custom keyboard shortcuts)

16.tab session manager

17.linkificator -- to convert links to clickable links

18.search by image

19.swift dial

20.custom google visited link color

21.custom scroll bars