Is there such thing as quiet billiard balls?

Answer 1

All pool balls are quiet until they collide with another ball. This happens only for a very brief fraction of a second during the typical pool shot.

Pool balls cannot be made of any other material that will change the sound they make on impact, so they cannot be quieter than they already are.

Answer 2

No. However, billiard balls are very quiet during play except when they contact another ball. So, they are quiet the majority of the time during a game.