If you're looking to shoot where it's safe and legal, but you don't want neighbors nearby to hear, consider the CCI Quiet-22.
Yes, it still provides a bang when fired in a pistol.
But in an older long-barrel bolt action .22 rifle, all I seem to hear is the slam of the firing pin, and a "thunk" when the bullet hits a thick aluminum target (old frying pan). Seems much more quiet than a spring-powered Diana air rifle.
Not a high powered round, but for plinking it gets the job done. Probably also applicable for small pests. At about 50 yards, no penetration of the pan, but a decent dent lays testimony to impact.