Thanks for the survey of similar applications. What I want is (inspired by Deep Work) an application that allows me to do time-blocking for a given day around my typical schedule.

For example, in a given day, since I'm a student, I may have two 75-minute blocks of class and a 45 minute meeting scheduled. I want an app that encourages me to think about what I'll be doing with the rest of my time and fill in the gaps in my calendar with whatever (reading, doing assignments, note-taking, etc.). Does one of the apps you've linked to provide this?