Audacity - Audacity is a free and open-source audio production software suite that includes a surprising array of editing tools and recording systems.
Fusebot - Write custom commands to integrate anything on Slack/Discord
WaveShop - Open source audio editor
Fluxpoint Development - Creating community projects, websites and tools since 2017
TwistedWave - TwistedWave is one of the unique audio editors that allow you to edit your music file online without any installation.
Mode - A complete analytical toolkit, free forever