Audacity - Audacity is a free and open-source audio production software suite that includes a surprising array of editing tools and recording systems.
Acoustica - Acoustica is an audio editing tool for editing, mastering and restoration work on both Mac and PC.
GarageBand - GarageBand is a fully equipped music creation studio for Mac
Reaper - Reaper is a focused digital audio workstation (DAW) developed by Cockos. In the creation of the software, the digital audio technology company intended to make audio editing accessible to the masses.
Adobe Audition - Mix, edit, and create audio content in Adobe Audition CC with a comprehensive toolset that includes multitrack, waveform, and spectral display.
Pydub - Pydub enables user to manipulate audio with a simple and easy high level interface.