As Rhett said, the 1946 Morley team RPPCs surface very infrequently.
There is also a very attractive set of individual player PCs from 1946 (see picture below).
Toughest of all in my experience is the
1948 multi-player postcard-sized, blank back set ( sample also pictured below).
The envelope for the 1947 cards is nice (and tough!) too, and addresses Rhett's comment about how they were issued and distributed
