In the Omori game you can obtain a number of keys. These keyboard keys are labeled with a capital letter. The letter keys start with A all the way to Z. You can find the R key here.
Omori Location Key S
You can find the Omori S Key in an enormous clam at the end of the Underwater Highway.
Looking for Key T. Find the Omori Key T.
You can find all Omori key locations here.