15HONORABLE MENTION: THOR
We can't talk about the times the shield was broken without mentioning the time it was dented. In 2003's Avengers #63 (Geoff Johns, Alan Davis), Thor became enraged when the nation of Slokovia outlawed the Church of Thor and slaughtered its followers. Thor tried to overthrow the foreign country because of
its betrayal, and the Avengers went in to try to stop their former teammate.
Iron Man, Captain America and Ant-Man engaged Thor in an epic battle. When Thor used his hammer on Captain America's shield, it actually managed to dent the indestructible metal. However, that didn't last long. When Thor calmed down and came to his senses, he used his hammer to bang out the dent, restoring the shield. It was the least he could do.