I use the Wayback Machine extension (<a href="https://chrome.google.com/webstore/detail/wayback-machine/fpnmgdkabkmnadcjpehmlllkndpkmiak" rel="nofollow">https://chrome.google.com/webstore/detail/wayback-machine/fp...</a>) - if a webpage no longer exists, the Wayback Machine will give me an archived copy of it.
Ublock Origin, Google Translate, Dark Reader, Picture in Picture, and Refined Hacker News are my favourites that I use most regularly.<p>But I have a soft spot for the Google Arts and Culture plugin:
<a href="https://chrome.google.com/webstore/detail/google-arts-culture/akimgimeeoiognljlfchpbkpfbmeapkh" rel="nofollow">https://chrome.google.com/webstore/detail/google-arts-cultur...</a><p>It gives you a fresh artwork for each tab you open.
I use Markdown New Tab. Basically it replaces your New tab with a markdown page with a built in editor. I then populate it with links I use every day, which is much faster than using bookmarks, and also reminder notes and whatnot.<p>I've found it to be so useful. And I love the fact that everything appears on all my devices that I use Chrome on, so I can also pass links to myself from my phone or whatever.
SingleFile for saving webpages that I can refer back to when my Internet is down and for private offline browsing:<p><a href="https://addons.mozilla.org/en-US/firefox/addon/single-file/" rel="nofollow">https://addons.mozilla.org/en-US/firefox/addon/single-file/</a>
uBlock Origin and Facebook Container. uBlock Origin is basically a content blocker. Facebook Container is preventing Facebook from tracking you.<p><a href="https://addons.mozilla.org/en-US/firefox/addon/ublock-origin/" rel="nofollow">https://addons.mozilla.org/en-US/firefox/addon/ublock-origin...</a><p><a href="https://addons.mozilla.org/en-US/firefox/addon/facebook-container/" rel="nofollow">https://addons.mozilla.org/en-US/firefox/addon/facebook-cont...</a>