Only three?
VSI, IVSI,
TEC VSI... all can be electronic or various kinds of mechanical devices (vane, twisted glass ribbon, diaphragm...).
Then you have VSIs and altimeters which connect to your GPS and handheld computer. You can get graphs of the lift around the circle while trying to center a thermal live on-screen. The gadgetry has advanced far!
I recently heard a description of how to prepare a real gadgeteer for flying in mountainwaves. "Place pilot in cockpit. Fill cockpit to rim with electronics. Put helmet on head of pilot. Send off".
Cheers,
Fred
Edited to add some highlighting
