Hovertimer

Just combine it with your favorite notes or mind-map app.

It can be used as stopwatch, countdown or as clock.

The maximum duration is 4 hours. There is no alarm sound when the countdown finishes.

Disclaimer: On iPadOS 13 the camera will not work in conferencing Apps like Zoom or Skype when Hovertimer is active. Future iPadOS versions does not have this limitation!