Polymail - This one is a lot like Twobird but with a lot more features. It's a different type of email client. It's really cool, but the Windows version is just a web app. It's available on iOS as well. Source: over 2 years ago

There is a free and open source app called SelfControl for macOS. It allows one to block access to any site one adds to the list in the app for the amount of time the user chooses. Attempt to use multiple browsers, restarting one's machine, deleting the app, etc. won't get around the block either. It's been super helpful for me, so I thought I'd just throw it out there. https://selfcontrolapp.com. - Source: Hacker News / 6 months ago

It is SelfControl. It is open-source and free. You select the website you want to block and the time. The moment you click the button no matter what you do, you can forget about accessing those websites until the time is over; there is no cancel button. Restarted mac won't work, you can delete the app no luck. Source: 7 months ago

The SelfControl app lets you specify web sites that will be blocked. When you run the app, you specify a countdown timer, during which time those apps will be inaccessible. Source: 7 months ago

- https://selfcontrolapp.com/ this is free app. block off all social media and time wasters .. Only for mac. if there is nothing to be distracted... IMO I eventually be bored and I was able to get into the zone... Not right away... But I told my self... Today I study... And I stay in the study room. Source: 7 months ago

Apps I have tried and are not enough: - https://heyfocus.com/ - https://freedom.to/ - https://selfcontrolapp.com/ - https://www.forestapp.cc/ - https://www.rescuetime.com/. Source: 8 months ago