BusyCal can manage all your tasks (also known as to dos or reminders). Tasks can be displayed in a Task List in the right sidebar and/or in the calendar on the date they are due.

Reminders is available as an app on iOS and macOS, which can include lists of reminders / tasks. BusyCal can connect to Reminders directly for syncing these lists their container reminders.

BusyCal now supports direct syncing with Apple Calendar in read-only mode for those instances where adding your account directly to BusyCal is not feasible.