Captain Chords - Write chord progressions in your favorite DAW
RapidComposer - MusicDevelopments RapidComposer: Music Prototyping and Automated Composition Software
Cthulhu - VST MIDI-FX plugin for harmonic inspiration
Helio Workstation - Cross-platform lightweight speed-painting tool for creating music.
Plugin Boutique - Inspirational MIDI effect that makes finding chords and progressions intuitive and fun
AutoTheory - MIDI FX songwriting tool to easily create professional scores over any chord progression