I don't know if these are good, or if they actually work, but I use them to train Hiro on something new.
Sniffers 101 All Natural Training Bits for your Dog
As well I give him a couple before bed -- and it might just be a huge coincidence -- but he seems to be pretty chill after I give him some. It says these treats bring focus and a calming effect over a pup. As I said, I don't know - but he loves them and so I use them.