This extension is my new favourite: https://addons.mozilla.org/en-GB/firefox/addon/leechblock-ng/
Other social media sites are on a strict time limit. (Mastodon isn't currently because it's not actively trying to hijack my mind.)
A mastodon instance for anyone who likes green, purple, any colour that can be mixed from green or purple, or any colour that can be used to mix green or purple.
Just a personal instance to experiment with Mastodon.