There is no end of productivity applications you can pay for, if that's what you want to do. What's rare is finding a totally free and high-quality application. Super Productivty might be an exception.
This free and open source application, which is available for Windows, Linux, Mac, and Android devices, combines a to-do list, time tracking, and time blocking. With it, you can quickly create a list of things you need to get done, estimate how long it will take you to do them all, and plan your time accordingly. The application is also built to track time spent on those tasks, helping you figure out how much time you're really spending on things.
Super Productivity, when opened, shows you your Inbox, where you can dump tasks as they occur to you. You can also set up projects and put your tasks there, if you prefer. After creating your tasks, you can add estimates for how long they'll take and even assign due dates. Then you can head to the Today, Schedule, or Planner sections and get organized.
The basic idea is that you can drag tasks into the order that you'll do them. The Today section will show you a simple list. The Schedule section will show everything on a calendar (which can also show appointments from any iCal calendar, including Google and Outlook). And the Planner breaks the list down by days. You can drag items from day to day, if you want.
Then, when you're ready to start working, hit the "Play" button in the top-right corner. This will start tracking the time it takes for you to finish the task currently at the top of the list. When you're done, you can mark the task as complete to stop the timer, at which point you're ready to start the next task. Your various views will show that the tasks are completed.
There's a few more tricks to be found in the settings, including a Pomodoro timer, a tool that regularly reminds you to take breaks, and simple counters for tracking things like how many coffees you've had.
It's worth pointing out that this app runs entirely locally—there's no web service. Syncing is handled by either Dropbox, WebDAV, or to other cloud services via a local file. There is optional support for encryption. This all means you're going to need to put in some effort if you want to use the app on multiple devices, but considering the application is free that might be worth it.
