SoundMaster is a nice and free control panel addition for System 6 or 7 that lets you set a custom sound to play for each specific Mac OS event, such as when you press a key, empty the trash, shut down your computer, etc... Starting from Mac OS...

Control panels to put in the System folder to use the Sigma Designs PageView / PageView SE card for external screens. At boot, if the screen is not connected, the control panel will show a dialog box notifying that there's no screen connected...

Control panel to re-scan and (un)mount SCSI drives

This Control Panel allows you to make tweaks to enhance the speed of your System 7 Finder

SoftwareFPU allows you to use software that requires an FPU on a Mac without an FPU.

Control Panel software version 4.0.1 for CoStar's Stingray trackball

SpeakTime is an extension and control panel which allow your mac to speak a user specified phrase on start up, speak the time at different intervals, and announce any number of custom phrases at user specified times and dates. It's been...

Patches the Appearance Manager to smooth fonts at less than 12 points.

Snap-To automatically moves the mouse cursor to the default button and can glide it smoothly towards it too.  Snap-To can also put the cursor back to its original location after a dialog window is closed.