I learned about these cards from the book Mint Condition by Dave Jamieson.
This first set was called Horrors of War and was published by Bowman (under the Gum, Inc, name) in 1938. This is pre-War World II and featured paintings depicting the various wars going on around in the world, such as The Japanese in China, the Spanish Civil War, and the Italians in Ethiopia. The cards were quite controversial at the time but also very popular with young boys. There are guite a number of them available on eBay. One of the controversial aspects was their brutal depiction of war. Many of the cards show very bloody scenes. I chose on which wasn't so bloody but is still pretty horribe.Twenty Naked Chinese Nationalists Charge Foe. The worst one I saw on eBay showed a decapitated head flying through the air trailing blood.
Bowman added the "To know the HORRORS OF WAR is to want PEACE" in order to claim that the cards were meant to be educational, not just sensational. I found a web site, Deke's Collections, which shows all the 288 cards.
This second set is generally called "The Civil War News" set due to the heading on the back of the cards. Long time Woody Gelman (the patron saint of Capewood's Collections") got the idea for this set from the Bowman Horrors of War set. The 88-card set was published in 1962. The official name of the cards is "The Civil War bubblegum set".
A pack cost 5 cents. Included in random packs was a Confederate Civil War bank note. I doubt they were real but I don't really know. There several sites which feature these cards. Try this one.