Ublock Origin is an obvious one, but I also can’t stand not having Foxy Gestures anymore. It adds customizable mouse gestures, so you can set it up to have easy swipes to go back a page, reload a page, close a tab, etc, and it feels wonderful and smooth to use compared to just using the traditional buttons to do everything. Honestly it’s kinda wild to me that this isn’t more popular now that people are so used to phone gestures. It’s good for the same reasons!
You can. But I use bookmarks for specific things I need to re-reference. And i use it in a more permanent manner. Especially when I want to access across different synced browser.
When I’m doing research or troubleshooting I will often have loads of tabs and searches open. This allows me to “wipe the board” and keep going or keep links specific to that browser iteration. It’s basically a halfway house to bookmarks for when I’m deep in some research on a topic where in the end I may come with 5-10 bookmarks that I do group of authoritative links.