Focuster is a task manager that automatically schedules your to-do list into your Google Calendar — assigning time blocks to tasks based on priority and available calendar space. Founded in 2015, Focuster addresses the fundamental disconnect between task lists and calendars: most people maintain both but manage them separately, leading to tasks that never get done because they were never allocated time. Its automatic rescheduling means that incomplete tasks are never lost — they simply roll forward to the next available slot in the calendar.

Reference:

Time Blocking on Wikipedia

https://en.wikipedia.org/wiki/Time_blocking