KMix is a sound channel mixer and volume control.

apps.kde.org/kmix
github.com/kde/kmix
invent.kde.org/multimedia/kmix
docs.kde.org/trunk_kf6/en/kmix
userbase.kde.org/KMix
KMix is a sound channel mixer and volume control.

apps.kde.org/kmix
github.com/kde/kmix
invent.kde.org/multimedia/kmix
docs.kde.org/trunk_kf6/en/kmix
userbase.kde.org/KMix
This application aims to provide a Fluent Design System based replacement for the old, built-in, Metro Design based Audio/Airplane mode/Brightness flyouts in Windows which are shown while pressing the media or volume keys or even the brightness keys or when airplane/flight mode is toggled.
In case of Windows 11, this application will have the same UI but will provide additional features and customizability compared to the built-in redesigned flyouts.

github.com/ModernFlyouts-Community/ModernFlyouts
modernflyouts-community.github.io
FluentFlyout is a simple and modern audio flyout for Windows, built with Fluent 2 Design principles. The UI seemingly blends in with Windows 10/11, providing you an uninterrupted, clean, and native-like experience when controlling your media.
FluentFlyout features smooth animations, blends with your system’s color themes, includes multiple layout positions and a suite of personalization settings while providing media controls and information in a nice and modern looking popup flyout.

Use this application to sync the volume of several audio playback devices.
sourceforge.net/projects/audiovolumesyncer
GVolWheel is a Linux application which lets you control the volume easily through a tray icon you can scroll on. Easily integrate with minimal desktops (Openbox,IceWM,XFCE etc).
github.com/Junker/gvolwheel
Volume² is an freeware app which is an advanced Windows volume control, a complete replacement for the default Volume Control on Windows. This application lets you easily change the sound volume just by rotating the mouse wheel or by using keyboard hot keys or just mouse move on screen border. The app comes with customization themes and interface and also other options like setting hotkey for changing volume.
irzyxa.blogspot.com
github.com/irzyxa/Volume2
Prevent someone from turning up the volume on a Windows machine beyond a maximum volume.
This is a very simple Windows Forms application that lets you set a maximum value on for your volume, and then lock the setting so that a user cannot change the volume.
Disclaimer: This app is primarily geared toward young/special needs children. The “lock” provides a basic level of control, but it could be easily bypassed by someone with technical knowledge.

Starting from Windows Vista, you are allowed to change the sound volume of every application separately, and after you exit from the application, the last settings are saved in the Registry under:
HKEY_CURRENT_USER\Software\Microsoft\InternetExplorer\LowRegistry\Audio\PolicyConfig\PropertyStore
So the next time you run the application, your last settings are used. This tool displays your current audio settings of every application on your system, and allows you to easily change the setting of multiple applications at once. You can change the mute/unmute status, the sound volume level, and the right/left audio balance of the application.

MicMute is a small program that will enable you to easily manage the level of a connected microphone. The application also supports push-to-talk thanks to the built-in ‘Transmitter Mode’. While it runs minimized in the system tray, MicMute can be controlled through keyboard shortcuts you choose. The software uses tray notification balloons and it also has a sound signal option you can activate.
Free Clip is an intuitive multi algorithm soft clipper / wave shaper plugin, available as a Windows VST or Mac Audio Unit. The plugin allows you to choose between a range of wave shapes or ‘sigmoid functions’, from the most transparent but harshest hard clip, to the ‘softest’ but most saturated arctangent shape. You can then intuitively set the ceiling level using the slider that perfectly matches the level meter next to it. Oversampling is also available to remove high frequency aliasing; when oversampling is on this does introduce peaks slightly over the ceiling level however, so if you intend to use this plugin with oversampling as the final plugin on the master chain, ensure the ceiling level is set appropriately and/or the post-oversampling clip setting is set.
This plugin is a great way to conveniently transparently boost volume without clipping your DAW, whether it be an individual stem or sound effect, or an entire track that you made. It is recommended that the hardclip, quantic or cubic shape be used for mastering, as these introduce no or minimal saturation.
The plugin can be also used as a more traditional saturation / distortion plugin by setting a ‘softer’ wave shape, such as algebraic or arctangent – simply lower the ceiling level to provide more saturation to the signal – just remember to boost the output afterwards. Alternatively you can boost the input gain into the clipper for the same effect. In this case, increasing the oversampling value is helpful if you’re hearing high frequency aliasing! Be warned that high oversampling values such as 16 or 32 times can be very heavy on the CPU.