Sound Control - App-specific volume control
Audacity - Audacity is a free and open-source audio production software suite that includes a surprising array of editing tools and recording systems.
EarTrumpet - Volume Control for Windows
FL Studio - Image-Line's FL Studio, now on it's 12th version, is a well-known music production suite and the most popular beat processor on the market, due no doubt to its longevity. Read more about FL Studio.
Volume2 - Volume2 is an advanced Windows audio mixer, a complete replacement for the standard Volume Control.
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.