Katana is a simple, open-source screenshot utility for macOS that lives in your menubar.
Pensela Alternatives
Pensela is described as 'Screen annotation tool that can also take screenshots available cross-platform' and is a screenshot capture tool in the photos & graphics category. There are more than 25 alternatives to Pensela for a variety of platforms, including Windows, Mac, Linux, Web-based and Google Chrome apps. The best Pensela alternative is ShareX, which is both free and Open Source. Other great apps like Pensela are Flameshot, Greenshot, Ksnip and PicPick.