Songstack - Swipe to discover new music for Spotify
22tracks - DJ curated Spotify playlists on iOS
BandNext - Discover bands that sound similar to artists you already love with BandNext. A single click saves your results to a Youtube playlist.
tradiio - Reward-based music discovery app
Noon Pacific - The week’s best music handpicked & delivered to your devices
Gnoosic - Even if you don't know what you are looking for - gnod will find it.