There is always this:
"Aguila .22 LR Super Colibri
The Super Colibri fires without a powder charge. It pushes a light 20-grain bullet at 500 fps
with little noise."
There are a few different quiet 22s currently available. You might note that the above is the "Super", they also make just plain old Colibri:
"AGUILA 22 LR 20 GR COLIBRI 375/FPS
This is a cartridge that contains no gunpowder. the little 20g. bullet is solely propelled by the powerful Eley priming mix. For this reason, it does not generate any significant pressure. Due to the lack of noise when fired, the .22 Colibri may be shot indoors, even in the living room
, provided a proper back stop is available."
CCI also just recently introduced "Quiet 22lr" and also has another slow and light weight .22 alternative the CB Long.
I shoot them all, gravity really is noticeable at rather short distances! Kind of like archery with a .22.