The American Colortype Company issued a set of 12 Valentines exclusively for Montgomery Wards in February 1940. Despite being licensed by Loew's for the MGM film, the card images alternated between W.W. Denslow styled characters and illustrations modeled after the MGM film personalities. Each card featured easel tabs for display. Though like the rest of the original Oz merchandising, the Valentines are scarce, they turn up frequently enough to convince me they must have sold rather well.
Not Shown: Tin Man & Scarecrow Valentine and Scarecrow with apple tree Valentine
Source: The Wizard of Oz Collector's Treasury by William Stillman & Jay Scarfone