FreePlay is described as 'true software based music accompaniment program that provides the same features and capabilities as an arranger keyboard. It works with any MIDI compatible music keyboard and sound module' and is an app in the Audio & Music category. There are three alternatives to FreePlay for Windows. The best alternative is VArranger. It's not free, so if you're looking for a free alternative, you could try Real-time Style Performer.
The Live-Styler is a fully equipped, software based computer organ. With it you can optionally operate 3 top manuals, 2 middle manuals, 2 low manuals and 1 bass pedal. The Live-Styler includes a complete automatic accompaniment.