1. Superman: In the famous "Death of Superman" storyline from the 1990s, Superman sacrifices himself to defeat the villain Doomsday. He dies after absorbing the energy from a nuclear explosion to protect Metropolis.
2. Batman: In the "Final Crisis" event from 2008, Batman is killed by Darkseid, a powerful New God. Batman is impaled by Darkseid's Omega Beams and appears to die, but he eventually returns in a later story.
3. Captain America: During Marvel's "Civil War" event in 2007, Captain America becomes involved in a conflict between superheroes over a registration act and is assassinated by Crossbones, a villain working for the anti-registration side. He later returns to life through various convoluted means in Marvel Comics.
4. Wolverine: In the "Death of Wolverine" storyline from 2014, Wolverine's healing factor is suppressed, and he is mortally wounded by a techno-organic virus. He dies peacefully surrounded by his fellow X-Men.
5. Spider-Man: In the controversial storyline "The Death of Spider-Man" from the early 1990s, Spider-Man is killed by the Green Goblin. However, this storyline was later revealed to be a hallucination experienced by Peter Parker, and Spider-Man continues to live in subsequent stories.
6. Green Arrow: During the "Crisis on Infinite Earths" event in the mid-1980s, Green Arrow sacrifices himself to save his team, the Justice League. He is crushed by debris after an attack on the satellite headquarters of the League.
It's important to note that these are just a few examples of superhero deaths, and many superheroes have died and been resurrected or retconned back into existence multiple times throughout comic book history. Additionally, comic books often feature alternate realities and timelines where different versions of superheroes exist, allowing for various interpretations and possibilities.