DAWs

• LMMS | FOSS | Powerful DAW with MIDI and VST support.
• Audacity| FOSS | Audacity is an easy-to-use, multi-track audio editor with VST support.
• Ardour| OSS |
• zrythm| OSS |

Plugins

Synthesizers

• Surge XT| FOSS | Great synthesizer with an extensive user made patch library.
• Vital | FOSS* | Solid alternative to Serum, optional extra patches and wavetables with the paid version.
• Cardinal | FOSS | Virtual modular synthesizer plugin based on VCV Rack.
• dexed | FOSS | Plugin synth that is closely modelled on the Yamaha DX7.
• Helm | FOSS | Polyphonic synth with lots of modulation.
• ZynAddSubFX | FOSS | One of the most in depth FOSS synthesizers.

Effects

• CloudSeed | FOSS | Algorithmic reverb plugin best employed as a special effect, for creating thick, lush pads.
• Surge XT FX | FOSS | Package of FX included with the Surge synthesizer.
• Airwindows | FOSS | Simplistic and experimental plugins.

Trackers

• sunvox | FOSS | Node based modular synthesizer with a pattern-based sequencer.
• OpenMPT | FOSS | Powerful tracker application that makes writing music fun, easy and efficient

Compositors

• Helio | FOSS | MIDI music sequencer, lightweight UI to help you get into the zone and focus on your ideas.
• Musescore | FOSS | music notation software.