In The Last Avengers Story, Wonder Man was part of a team of Avengers who confronted Ultron-19 including Hawkeye, Mockingbird, Tigra, and the Hulk. Unfortunately, the Hulk had been driven to evil by a Great Cataclysm he fought in between Asgard and Olympus, and turned on his teammates. He snapped Tigra in two in front of Simon's eyes, making the fight a battle to the death from then on. Mockingbird evacuated Hawkeye as two of the strongest men on Earth fought tooth and nail. Finally, the Hulk struck hard enough to rupture Wonder Man's indestructible skin, but in doing so he triggered an ionic meltdown. Simon held the Hulk in close as his ionic energy erupted outwards in the equivalent of a multimegaton nuclear blast, consuming the two combatants entirely.
Wonder Man was one of the people constructed by Franklin Richards to populate the Heroes Reborn universe. He initially approached the Avengers as if needing help, but was soon revealed to be a villain working for Enchantress and Executioner as part of the Lethal Legion. The Avengers battled the Lethal Legion and other forces like the Masters of Evil as part of a larger manipulation set in motion by Loki.
After the Kang War, life on Earth became virtually uninhabitable. The unhinged Tony Stark and Suzi Endo created a world of unchecked industry and bio-mechanical syntheses that changed humanity for good. Some robotic beings like Ultron became techno-organic flesh and blood, while Wonder Man was restored as an unfeeling mechanoid. Suzi Endo, Cybermancer, traveled back in time to help Kang's modern era puppet Iron Man change history and wreck the Avengers and Force Works. Wonder Man and Ultron followed her back through the time corridor and confronted Force Works. The time corridor became unstable as their entire future timeline was consumed and destroyed, leaving Wonder Man and his allies to dissipate into nothingness.
In the future of the Guardians of the Galaxy, the early 21st century was marked by the War of the Worlds as invaders from Mars dominated the planet Earth. Most of Earth's Mightiest Heroes fell in battle with the Martian Masters, leading to decades of enslavement by the invaders. When Vision calculated there was no hope in winning the war, he teleported his brother Wonder Man away from the planet. This was a cruel fate for Simon, who returned to Earth too late to stop the conquest by the Martians. Worse, Wonder Man became a punchline among the surviving humans, mistakenly believed to be a coward who ran away in Earth's time of need.
The Martians were eventually deposed, only for Earth to be conquered again in the 31st century by the Brotherhood of the Badoon. Once the Guardians of the Galaxy cast off the Badoon occupation, much of Earth devolved in gang violance and factionalism. Under the assumed identity of Hollywood, Simon Williams fought as a member of the Commandeers. He would eventually serve with the splinter team of Galactic Guardians, although he was slow to forgive his brother Vision, now known as the sentient world Mainframe. Hollywood also became a member of the original Guardians of the Galaxy roster as well.
Wonder Man's immortality was on display in the limited series Wonder Man: My Fair Superhero. The modern era story was told via a framing sequence where an older Simon wandering the devastated and abandoned Earth. He reflected on entire civilizations that had passed by his immortal eyes while remembering the life he once led.
In Earth X, Wonder Man was one of the many occupants of the realm of the dead, believing himself to still be alive while trapped in an endless conflict. He was eventually awakened to his true circumstances, and became an ally of Captain Mar-Vell in reshaping the rules of the Marvel Universe for the better.
Ultimate Wonder Man began as a champion bodybuilder. Simon Williams received endorsements and the adoration of the public for his strength and skills until a doping scandal revealed he had used performance enhancers illegally. At loose ends, Williams was recruited by Nick Fury to join the West Coast Ultimates. This unit proved unstable, however, and Wonder Man was no exception. The unstable Super-Soldier Serum that created his powers caused Hulk-like increases in mass and aggression. The West Coast Initiative was put on ice, literally, and held in cold storage in California. When the country became divided, a political mover named Ford released the West Coast Ultimates and manipulated them into attacking Captain America and his government.
In What If? (2nd series) #5, Wonder Man confessed Zemo's plan to the Avengers after meeting them instead of following through with it. As a result, Giant-Man and Reed Richards had time to develop a serum to cure Simon's ionic poisoning, and he became a mainstay member of the Avengers. Wonder Man and Captain America were the only hold overs on the roster when Quicksilver, Scarlet Witch and Hawkeye first joined. Simon and Wanda were attracted to each other early on, but Pietro refused to allow his sister to be with anyone other than him. Simon and Wanda's love could not be denied, however, and Quicksilver eventually left the Avengers in a rage. He returned in the identity of the Grim Reaper and teamed with Magneto, leading to his death and Wanda killing Magneto in turn. Wonder Man proposed to Wanda after that, and they became the second married couple in the Avengers after Hank and Jan Pym.
Without Wonder Man's preserved brain wave patterns, Ultron decided to animate the synthezoid body of the Vision himself. This synthetic Ultron attacked the Avengers, causing severe injuries on the team. Wonder Man suffered the worst when Ultron plunged an intangible fist into his chest and solidified it, a fatal wound. Simon Williams died but, as he did in another reality, Hank Pym preserved his brain wave patterns and carried them over into the next available body...the synthezoid. And so, the mind of Wonder Man lived on in the Vision in this reality as well, leaving Wanda Williams to adjust to the changes in her husband.
Simon Williams was one of the most popular super-beings in the House of M reality. Although not a mutant, his superhuman nature delivered him near equal status to Homo Superior in Magneto's world order. Simon was romantically linked to Carol Danvers, alias America's most popular hero Captain Marvel, and it was also rumored he was the illegitimate father of Wanda Magnus's youngest son.
On Battleworld, a version of Wonder Man lived beyond the Shield as part of a trinity with Vision and the original Human Torch. Their incarnation of Ultron killed his Avengers and established a robotic city known as Perfection. Wonder Man and his allies distanced themselves from Ultron and founded their own city, Salvation, as a place of safety for those people exiled beyond the Shield Wall. Simon's engineering know-how combined with his ionic energy and tech salvaged from Ultron allowed them to create an impenetrable barrier to keep out the robot hordes and zombie scavengers of the neighboring Deadlands. Wonder Man had a relationship with his fellow refugee, Iron Cross.
When Ultron cybernetically merged his technology with Magneto and his zombies, Salvation faced extinction. A recently rescued version of Hank Pym developed the means of shutting down Ultron permanently, but it would require the sacrifice of Wonder Man, Vision, and the Torch, shedding their individuality to became a singularity capable of producing the frequencies Pym needed. Simon was prepared for this sacrifice, but Iron Cross wouldn't let him make it alone. She had Pym upload the necessary data into her own bio-mechanical components, allowing her to replace the Human Torch and merge with Simon in the trinity so they could remain together.
Another version of Wonder Man from Battleworld was Baron Simon Williams of the Holy Wood domain. The Wonder Man and his Avengers were neighbors to the domain of Forest Hills and its Baron Michael Korvac. Although ostensibly allies, Baron Williams was angling to take over Forest Hills by having God Doom declare him baron of both domains. He saw a political opportunity when Forest Hills was subject to the Madness, an infectious idea that there was once something greater in the universe than God Doom and his world. This heresy proved too great for Doom to tolerate, however, and he sent his Thors to annihilate both domains. The Wonder Man declared his faithfulness to Doom, but the Thors cleansed him regardless as the will of God.