LibriVox - free public domain audiobooks

Sleep Cycle - Bio-alarm clock that wakes you up at optimal times based on your sleep patterns.

Audible - Audible is the world’s largest provider of premium audiobooks and spoken word content.

Sleep as Android - Common alarm clocks ignore your sleep cycles, they wake you on schedule no matter your are currently in your deep sleep. Waking up from deep sleep is unpleasant, it makes you tired and it may negatively affect your productivity during the whole day.

Libro.fm - A digital audiobook platform for independent bookstores

Talalarmo - Minimalistic android alarm