MbiraGen is a free semi-generative sequencer vst plugin that produces MIDI notes based on a sequence of up to 12 “melodies”. Each melody can have up to 4 variations which are selected round-robin. A Melody is a 5×4 grid where the vertical direction indicates note pitch and the horizontal direction indicates time.
Nova3 is a free VST Generative Sequencer plugin. The plugin is for Windows only, and includes an x32 and x64 version.
Regen is at its heart a looper plugin that is well suited for ambient / textural / soundscape type layering. It can be a simple looper but also offers deeper dive controls to modify playback of recorded material.
GrainMaker is a free 32-bit VST plugin for granular processing. Lots of modulation options.
Delay8 is a free delay effect VST. It has eight individual modulated delay lines which may be combined in serial or parallel chains. Individual modulation, EQ, panning for each delay line. Global scaling knobs to adjust the overall character of the effect. Stereo in, stereo out. Good for choruses, diffusion, modulated delays. Windows VST 2.4, x32 and x64.