A sound level manager
gnome-volume-manager is a desktop-level daemon that enforces volume-related policy in response to events received from HAL.
KDE Volume and Partition Manager
A tool that handles hot-pluggable devices and removable media that are added to or removed from the system.
osdvolume is a little daemon to use mainly with notebooks, that will adjust the volume and displays on OSD as KOSD.
wmVolMan is a small volume manager for Window Maker.
Thunar Volume Manager project provides automatic management of removable media and drives for the Thunar File Manager.
Ivman is a flexible userspace volume manager for Linux.