Which Firefox extensions You found usefull?

mine firefox addons:

Decentraleyes (privacy, speed)
Google search link fix (external links on google SERP are direct, not prefixed by google domain)
HTTPS Everywhere OR ConsistentHTTPS (go via secure https when possible)
Imagus (mouse over image thumbnail to show full size)
Fast Image Research (right click image to find similar/same on google)
IP Address and Domain Information (discover website details)
Load from Cache (cache web content to HDD as much as possible)
Page Shadow (dark backgrounds on sites)
Textarea Cache Lite (recover lost text in text areas)
uBlock Origin (block many ad networks/banners and useless traffic trackers etc.)
Video Downloader professional (download streamed videos from various video sites, except youtube)
Zoom Page WE

less important:
Snapped Padlocks (shows unsecure icon on HTTP only sites in address bar)
Stay-Open Menu (open multiple bookmarks without closing bookmark menu)