Blacklist is described as 'A iOS app to block websites for a certain amount of time'. There are more than 50 alternatives to Blacklist for a variety of platforms, including Mac, Windows, Android, Google Chrome and Linux. The best alternative is Cold Turkey, which is free. Other great apps like Blacklist are LeechBlock (Free, Open Source), Forest (Freemium), Freedom (Paid) and StayFocusd (Free).
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.
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.
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.
Focus is a Mac app that blocks distracting websites (like Facebook and Reddit) and applications, so you can improve your productivity. It has lots of awesome features like scheduling, showing motivational quotes on blocked pages, whitelisting and pomodoro support.
BrowseControl is an agent-based web filter that blocks websites based on URLs and categories. Internet use quotas can be set based on schedules and timers. Includes a port filter and Windows application blocker.