There is currently no way in SAP standard to report usage of SAP Fiori applications (see SAP notes below) meaning, users can’t run the report and have the list of most popular SAP Fiori applications.
This is something many people have been looking for since the beginning of the SAP Fiori offering. So we (at Nype) have prepared the solution, which is based on the SAP Fiori launchpad plugin and the catalog of all the apps in the scope – you have a clear view on all started application details and their link to SAP Fiori library id. The report runs in the central system (you can choose SAP Solution Manager for that) that collects data separately for each of your systems in your system landscape.

Here is how the report looks:

You can install the “Apps usage report for SAP Fiori launchpad” by downloading the transport from GitHub:
https://github.com/fioritracker/installation
And following those two install guides:
https://help.fioritracker.org/1909SPS06/#/installation-guide/basis-steps
https://help.fioritracker.org/1909SPS06/#/installation-guide/plugin
The report was priceless during the implementation when testing. It was also a huge help when deciding on the priority of adjusting the apps after the upgrade. As well as deciding on the business impact when users reported issues with specific apps. We also used it to detect scope creep – this is especially important when the number of custom and extended apps grows, and the project is not tracking who is responsible for maintaining new apps.
SAP notes on usage reports in SAP standard: