SimpleBlock od Steven Gutierrez

Prevent yourself from mindless scrolling by blocking the homepages of your favorite time wasters while you focus! Still need to stay in touch? Redirect your social media homepage to messages so you're still able to chat, but prevent yourself from doomscrolling.

Features
Simple Unlimited Ruleset: Create rules to block or redirect specific websites or pages
Flexibility: Block a single page, or block a whole site. Or redirect them back to your work
Focus Mode: Enable and disable rules on-demand for ultimate control over your browsing experience

SimpleBlock is open source!
https://github.com/Seltonu/SimpleBlock