M3 x 7mm Anti-Vibration Flight Controller Soft Mount Standoff 4 Pack

They are good quality. And semi soft mount your fc.

Efficient vibration damping

These are the best for vibration damping, because the metal screw doesn't go through. Vibration transmission is completely damped by the rubber part in the middle.

Perfect

These did exactly what I needed they are nice and flexible but not too flexible. The help the gyro wiggle around and keep it dampened from crashing and normal vibrations. One thing I did notice is the female threads inside can be a little short so make sure you account for that. Other than that the install was easy