Cardinal is a free and open-source virtual modular synthesizer plugin.
It is based on the popular VCV Rack but with a focus on being a fully self-contained plugin version.

Cardinal provides 3 plugin variants - "main", Synth and FX.
They are all equivalent in performance and behaviour.
FX and Synth variants both have 2 audio outputs, while "main" has 8.
All variants have MIDI input and output support.

This package provides the AU, LV2, VST2, VST3 and CLAP audio plugins, plus standalones for both JACK and native audio/MIDI.

Notes:
 - Due to AU and VST2 not supporting CV ports, the main variant is not available for these formats
 - The standalones are intentionally very barebones in terms of system integration, prefer to use the plugin versions if you can