Audacity - Audacity is a free and open-source audio production software suite that includes a surprising array of editing tools and recording systems.
Tenacity - Tenacity is an easy-to-use, privacy-friendly, FLOSS, cross-platform multi-track audio editor/recorder for Windows, macOS, Linux and other operating systems.
DarkAudacity - DarkAudacity is a build/fork of Audacity with quote "a darker more modern theme - and a few small tweaks."
Spek - Spek helps to analyse your audio files by showing their spectrogram.
Mp3MyMp3 Audio Recorder - MP3MyMP3 is a handy and easy-to-use software utility that enables you to record audio from different sources like any system connected through the audio card of your computer or a connected microphone.
AudioMass - A full-featured web based audio editor 🎶