Hi,
Keynote has a custom animation function that animates changes between transitions and export them as an animated gif.
One use case was animating icons over a static page of a webpage to explain how to use a website.
You can see more here:
or here:
Does Impress have this functionality.
The only thing I could find was this help section animating objects, but the custom animation menu item doesn’t seem to exist anymore:
https://help.libreoffice.org/Impress/Animating_Objects_in_Presentation_Slides