Preferably lesser known but game-changing apps that are able to be bought one-time and put all others to shame.
To help clarify your thinking, which apps have produced such an outrageous level of value (regardless of one-time cost) to the extent you believe it should be #1 in its category, not necessarily #1 app ever.
We’ll do a seperate thread for Mac, Windows, Linux, Android, etc but let’s stick to iOS for this one. Thanks Lemmings!
Glazba. It’s a music player that allows for playing files in various formats, including FLAC. Song files can be uploaded to the phone through the app via web browser over Wi-Fi, or it can play music files stored on any of several cloud-storage services. Considering that I’ve ripped my entire 1000+ CD collection to FLAC, and considering that it contains a number of albums not available through streaming services, this app has been quite useful.