I like progress bars in presentations instead of tiny numbers in the corner of each slide and there is a interesting way to create them in LibreOffice Impress automatically, using macros.
First, go to github.com/dasaki/Impress-Progress-Bar, download the zip and unpack it.
Second, you have to import the macro into LibreOffice. Go to Tools → Macros → Organize Macros → LibreOffice Basic → Organizer → Libraries → Import (long way, I know...). Find the unpacked files and open one of them. Then, the macro will be available for you to use.
Third, use it! When you finish your presentation, go to Tools → Macros → Run macro, find the script called ProgressBar and click Run. It will show a dialog with a few options and when you close it, the macro will create rectangles in your slides showing the progress of your presentation. After that, you can edit them (even delete them) as you wish, but at least the insertion with the correct size if done for you.