Battle Covers: Avengers #53 (6/68: John Buscema), Avengers #70 (11/69: Sal Buscema), Fantastic Four #73 (4/68: Jack Kirby). There are probably more like this that I'm missing ... ? : r/comicbookcollecting
Avengers #53 (Marvel, 1968) CGC NM 9.4 Off-white to white pages. | Lot #16065 | Heritage Auctions