While we don't yet have a dedicated case for the Zoom R16, one of the cases in our PULSE line may be a good fit!
The dimensions we have on hand for the Zoom R16 are: (14.8 x 9.33 x 2.06) inches. If that aligns with what you have, we would recommend looking at the PULSE Case for the Korg Monologue: 15.25 x 11 x 2.75 inches.