"Tarot on the Go"
Miniature Rider-Waite-Smith & RWS Clone Decks
I have to say, the more I use these, the more I like them, & I highly recommend them. But there are some things to be aware of before buying. If you are looking for them to look exactly like the large Universal-Waite deck, they don't. You can read an extended review here.
The standard U.S. games version of the RWS deck, but in pocket size. (Similar to playing card size.) They may be out of print, but at this writing, there appears to be one available through Amazon Marketplace.
The pocket version was one of my very early decks. I used it until the cards were so thick I could hardly shuffle them. Very nice size to carry around.
Smaller yet, the mini deck is another that's great to carry around. Never know when someone may want a reading. ;-)
This is one of the few decks on these pages that I don't personally have because they just look too small to me, but since I'm so hot on the Universal Deck, I thought I would at least make a mention of them here.
From what I hear, they are about the size of a postage stamp and come on a key ring, so really, they don't sound practical for reading purposes, but certainly they might be a cute little item to have for a collection or a key ring.