Todoist, Microsoft To Do, Google Calendar, Notion Calendar, Fossify Calendar, Lightning Calendar, Proton Calendar, Tasks.org, Remember The Milk, One Calendar, Me Calendar, sleek, Desktop Calendar, Calendar 366, Desktop iCalendar, Simple Calendar, Itsycal, Calcurse, jquery-calendar, UKs Kalender, RemindMe desktop calendar, Vantage by 44, 30 Boxes, GMinder, gsimplecal, CalendarWiz, Google Calendar Checker, Calbird, Caliander, Peek Calendar, vircorX, PreMinder, Handy Calendar, Polar Liquoo are some alternatives to Kalendar.