Pictured below are the Superman-related stickers in the 1978 DC Superheroes promo set. These 2-1/4″ x 3″ stickers were inserted in loaves of bread, and were available in Sunbeam, Taystee, and Langendorf breads, each with the company logo on the front. Also available, shown below, was a blank set with no company logo. The backs of the cards each feature a paragraph description of the character, the card number out of 30, trademark information, and “Produced by Arnold Harris Assoc., Inc.”
Out of the 30 sticker set, 16 show Superman or his supporting players, including Lois Lane, Jimmy Olsen, Perry White, Krypto, Ma and Pa Kent, Jor-El and Lara, Supergirl, and Lex Luthor, who is the only Superman villain in the set.
I’m missing sticker #17, Good Vs. Evil, showing a fight between Superman and Lex Luthor.
The stickers are unsigned, so I don’t know who the artists are, but The Aquaman Shrine IDed the artist of the Aquaman card as Dick Giordano. I also found this auction for original art that identifies the artist on #8 as Ross Andru and Dick Giordano.