There is a lot of stuff but for me the main one is to control the playback speed with mouse just hovering over the extension UI and scrolling mouse. You also have a SS function on a button and multiple ways to change your player window, all of this with a simple UI below or embedded in the the video player (you always use to hover over the buttons).

There is some extensions out there that can do most of these features but I always found them too cluttered if they have an UI or too clunky if they use gestures over the player. I always do shit while scrolling my youtube pages using the Tweaks for youtube extension cause my mouse were always in the wrong place while scrolling and I slow the video instead.

Sorry for not putting a link in the OP, I was in a rush to post here, I know that a lot of ppl were orphan like me.

firefox store