SelfControl -- The Linux port Alternatives

LeechBlock is a simple free productivity tool designed to block those time-wasting sites that can suck the life out of your working day. All you need to do is specify which sites to block and when to block them.

Cold Turkey is a productivity program that you can use to temporarily block yourself off of popular social media sites, addicting websites and games so that you can get your work done!

Forest is an app to help you stay focused on your work. Whenever you want to concentrate, you can plant a seed in Forest. In the next 30 minutes, this small seed will gradually grow into a big tree.

SelfControl is a free and open-source application for Mac OS X that lets you block your own access to distracting websites, your mail servers, or anything else on the Internet. Just set a period of time to block for, add sites to your blacklist, and click "Start.

StayFocusd is a productivity extension for Google Chrome that helps you stay focused on work by restricting the amount of time you can spend on time-wasting websites.

Freedom is an application that disables networking on an Apple computer for up to eight hours at a time. Freedom will free you from the distractions of the internet, allowing you time to code, write, or create.

Iris is software which makes monitors healthy for the eyes. With iris you can reduce the blue light emitted from your screen for better sleep, reduce the brightness of your screen without PWM and avoid eye pain.

Focus is a Mac app that blocks distracting websites (like Facebook and Reddit) and applications, so you can improve your productivity.

Motion helps you stay productive on your computer by reducing time wasted on distracting sites and improving focus on the tasks you've set out to finish.

There’s no shortage of productivity tools, but most solve a piece of the problem – blocking websites, or playing concentration music – rather than solving the entire problem.