If you're looking for a calendar app that's tightly integrated with your email client and that lets you schedule things with a few clicks, Dola could be the way to go. It links to Google Calendar and Apple Calendar, among other calendar apps, and accepts input in several formats, including voice, text and image. Dola's AI technology lets you manage and sync calendars across all your devices, and it can automatically send you calendar events and calendar tasks to keep you on track.
Another contender is Clockwise. This calendar optimization system uses AI to schedule meetings and tasks, but also to schedule focused time and to take breaks between meetings. It can link to Slack to synchronize your calendar and status, and it can generate dynamic scheduling links and recognize travel time. Clockwise is designed to cut the time you spend coordinating and to help you get more done, so it's geared for high-powered professionals.
If you're more of a task manager, SkedPal pairs advanced algorithms with an interface that's designed to be easy to use to help you set priorities and schedule your time. It can link to Google, Office 365 and iCloud calendars, and it's got features like nested task lists, rich text notes and file attachments. SkedPal is geared for people with complicated lives, and it's designed to help you get a handle on multiple commitments.
Last, fwd2cal is an open-source tool that can automatically add events to Google Calendar from email threads you forward to it. It can handle multiple email addresses and preserves privacy since it doesn't store emails. If you want to keep your email data private but still have your calendar updated automatically, it's a good option, and it's useful for scheduling appointments.