ChordFlow
Chord sequencer with a unique built-in arpeggiator and extensive chord library for iPad, iPhone and iPod touch
https://itunes.apple.com/us/app/chordflow/id1219789464?mt=8https://www.ableton.com/en/link/
https://audiob.us/
Use it as a songwriting tool 
Create lovely chord progressions. Draw beautiful arpeggio patterns using simple and intuitive tools. Save your songs for the future inspirations. 

Use it as a backing track tool
Create a chord progression, select a looping mode and practice your solo on your favorite instrument or sing along with ChordFlow.

Use it for live performance
Prepare multiple sections with different chord progressions and different arpeggiator patterns. Loop a section or a specific chord, jump between sections or chords on the go. Edit arpeggiator patterns while playing to add variation to your performance. Play in sync with other apps using Ableton Link.

Features
- More than 50 chord types available.
- Intuitive tools for drawing arpeggiator sequences.
- 1 to 32 steps arpeggiator
- 4 tracks in a arpeggiator sequence. Each track can be assigned to the individual MIDI destination/channel.
- 3 sequencer looping modes: one pass, loop selected, loop all.
- Quantised jumps between sections.
- A song can be split by any number of sections each containing different chords and arpeggiator sequences.
- MIDI Out to any CoreMIDI compatible app, USB or WI-FI
- Ableton Link support
- Audiobus support (provides 1 Audio sender port and 5 MIDI sender ports)