uBlacklist: block SEO, clickbait garbage from Google search
Shutup.css: blocks comments on all websites; I enable it on websites (such as lemmy) in which the website is dedicated to discussion. This prevents me from seeing stupid MSN like comments.
AdBlock: Blocking ads. They are slow, they are annoying, they follow you and I hate them.
Privacy.com cards: Lets me lock a card and certain amount to a website I may or may not trust, and prevents them from charging more than I state. Has been VERY useful for Amazon Eero in which they keep auto subscribing me to eero Plus and “don't know what happened on their end”.
This is more so related to Xbox, but:
Filtering all messages from people who aren't my friends into a separate inbox that doesn't notify me. Blocking party invites from people who aren't my Xbox friends (prevents assholes in Overwatch from DDoS).