FocusList is a simple, good looking Pomodoro app for macOS, iOS and Apple Watch.
It's based around a task list: You can't just start a timer, you have to create a task first, and then you can start a timer for that task.
The task list has a special feature. For each task, you can set an estimated number of Pomodoros. As you work through them, it keeps counting the completed ones.
FocusList is $4.99 for macOS version and $4.99 for iOS version, and your data is kept in sync through a custom sync solution.