This free and open-source [Timer app][1] seems pretty clean and simple.

It can be downloaded as the zipped file **Timer.app.zip** in the **Assets** list on the [Releases · michaelvillar/timer-app][2] page at GitHub.

It can also be installed using brew:

    brew cask install michaelvillar-timer

[![Screenshot of Timer app][3]][3]

  [1]: https://github.com/michaelvillar/timer-app
  [2]: https://github.com/michaelvillar/timer-app/releases
  [3]: https://i.sstatic.net/v4SxF.png