Some sort of g-meter" and accelerometer," too. The first would tell you approximately how many g's you're pulling before you start to gray or red-out due to GLOC. The second would simulate the feeling of being pushed back in your seat as you accelerate, being pushed forwards as you decelerate or "hanging in space" as the plane "drops out from under you" in a stall (or as you start to "fall out of the airplane" when flying inverted).