About 6 years ago I bought 'Screen Grabber' in App Store. I still use it and it's not available anymore in App Store and development stopped many years ago.
The developer wrote me:
I am now employed by Apple, and can no longer maintain the app due to internal policies.
I do not know of any alternatives, sorry. I have released the app as open source for anyone else to use. It should build with free Xcode from Mac App Store; https://github.com/PeyloW/Screen-Grabber
// Fredrik Olsson
the only alternative I know is CLI tool Video Contact Sheet *NIX, but sadly not the usability of Screen Grabber.
other recommendations? What you use?