The free version of the apps Tempo Trainer Prime, Little Goddess and the Universal Converter Prime, contains ads by Google (Google does collect data with their ads). Other than that, no data is collected. The Tempo Trainer Prime Pro app does not collect any data on your usage. For both apps, no data is collected by and/or transfered to me (as a developer).
The privacy policy of the free version of the app is developed according to this webpage.
Tempo Trainer: Here you can find the free version with ads and the paid version without ads.