Things 3 is a best-in-class task manager for macOS and iOS. Unfortunately, it lacks an API, support for other platforms and more functionalities to make it a true productivity companion.
Routine combines tasks, notes, projects, contacts, calendars and more (through custom types) into a beautiful all-in-one productivity app. Even more, Routine integrates with all your favorite tools. You can finally bring all your data from Gmail, Slack, Github and more into a unified workspace to manage your life and work.