There are lots of different simple app ideas in the productivity segment. These categories include:

• Calendars (Google Calendar, ZenDay, Jorte)
• Checklists (Toggl Plan, Any.Do)
• Communications (Slack, Microsoft Teams)
• Database management (DbVisualizer, Microsoft Access)
• Presentation (Google Slides, Canva)
• Project management (Basecamp, Asana)
• Resource management (Trello)
• Task management (Todoist)
• Time tracking (Hubstaff, Focus Plant)
• Word processing (Grammarly, Wordpad, FocusWriter)

An example of a task management app by Shakuro