Firefox

Especially ones that you find useful on android Firefox, as they seem to be less popular?

Recently got to know about bookmarklets due to a thread here in this community itself:
https://lemm.ee/comment/12623456
^An unrelated question: Is there some way to link comments so that they are automatically opened in home instances for eveyone, like how we can link communities and usernames currently?^

Some interesting/useful bookmarklets that I know of:

1. Bullshit.js as mentioned in that link
2. dotepub. It does say that data is sent to their server.
   For some sites it's better than the inbuilt save as pdf option.
3. A bookmarklet that opens the current site in G-translate
4. Saw a bookmarklet which works like reader mode.

The freecodecamp article on bookmarklets maybe useful for those new to it(It helped me). It seems cool.
https://wiki.greasespot.net/User_Script_Hosting links to sources for userscripts. Most of them seem to be desktop-centric.

Which are your favorites? Any cool ones that you have made on your own?