The Lemar Hoskins, known as Battlestar. And, many different characters have been Bucky in the main Marvel Comics universe over the years.
There have also been several alternate versions of the character from different realities and timelines. All of them connect to the original Bucky Barnes in some way, but provide different interpretations of the character's background, powers, and history. Most of the Buckys have been heroes, but not all of them.
Julia Winters "Baby Bucky"
One of the strangest Buckys in the comics is Julia Winters or the "Baby Bucky." She was an infant girl adopted by the second Bucky chronologically, Jack Monroe. At the time he took in Julia, he was acting as Nomad.
She debuted in the 1991 Nomad limited series written by Fabian Nicieza and drawn by James Fry. Nomad called her Bucky and even dressed her up in a baby Bucky outfit, while he tried to find her birth mother. She was later adopted by a new family and Julia hasn't been seen in the comics since.
Rick Jones
The third character to inherit the role of Bucky in the comics was Rick Jones, who is perhaps best known for being the friend of Bruce Banner, the Incredible Hulk. Jones looked so much like Captain America's sidekick Bucky Barnes that Steve Rogers actually thought it was him.
Jones gradually fell into the role of Bucky, acting as Captain America's sidekick for a while, but Rogers' latent grief about Barnes eventually made it too hard for either of them to continue and Jones abandoned the role.
Ultimate Bucky
In the original Marvel Comics, before the retcon of Bucky being The Winter Soldier, he had died in World War II. In the Ultimate Comics universe, which started in the early 2000s to bring new readers into Marvel Comics without the burden of continuity, Bucky never died. He survives to the present day, an elderly man suffering from cancer.
He's reunited with Captain America after he comes out of the ice, but their adventures aren't over. He discovers that the Red Skull, one of the most powerful Captain America villains, is the son of Steve Rogers and Bucky's wife, Gail.
White Skull
The Red Skull would loom large in another alternate version of the Marvel Universe. In What If: Captain America from 2005, Bucky becomes a villain known as the White Skull. This version of the classic Captain America occurs during the Civil War rather than World War II, with Barnes as a duplicitous Union colonel.
Barnes' skin is burned away and he's left only with his terrifying skeletal visage. He didn't have any superpowers, but was cunning and skilled in battle, making him a dangerous foe.
House Of M
House Of M was a seminal comic book that heavily influenced WandaVision. In the alternate reality that Wanda Maximoff created, Bucky Barnes is a government agent tasked with a very important mission: killing Magneto, the head of the House Of M and leader of Genosha.
He arrives in the country on a clandestine mission and succeeds in killing Charles Xavier, but fails to take out Magneto. Magneto doesn't miss, though, and kills Barnes. He shares the enhanced strength and skills of the main universe Bucky.
Rebecca Barnes
One alternate version of Bucky comes courtesy of the Exiles, a dimension-hopping team of superheroes. They visited a dimension where Steve Rogers died before taking the Super-Soldier Serum. That fell to Peggy Carter, who became a version of Captain America in his place.
She took in Rebecca Barnes, who became her sidekick. After Peggy and other heroes died in the war, Becky as she became known ed the Exiles. She eventually developed a relationship with teammate Valkyrie, who was based on the MCU version of the character.
Rikki Barnes
Another female version of Bucky also hails from a different reality. In the 90s, the Avengers and Fantastic Four were cast away to a pocket universe during an event called Heroes Reborn.
In that universe, fans met Rebecca "Rikki" Barnes, the granddaughter of Peggy Carter. She puts on a costume and becomes the new Bucky, fighting alongside Steve Rogers. A version of her eventually arrives in the Earth-616 universe, where she becomes Nomad, and battles against the second version of the Flag-Smasher.
Fred Davis
Fred Davis is an alternate Bucky from another What If..? story. He first appeared as Bucky in What If..? #4 in August 1977. In this story, Davis takes up the mantle of Bucky after both Barnes and Captain America have been killed. After the war, he ed the V-Battalion, an organization dedicated to hunting down war criminals.
Davis remained with V-Battalion for the rest of his life, bringing criminals to justice all over the world. He was eventually killed by a Red Room assassin, who was seeking out and destroying all Buckys. Unbeknownst to Davis, Barnes was still alive as The Winter Soldier.
Nomad
In continuity, the first man to take the mantle of Bucky after Barnes was Jack Monroe. He took the same Super-Soldier serum that created Captain America and fought side by side with him in the early 50s as Bucky.
All of this came about through a series of retcons in the comics, as Monroe actually wasn't introduced until Captain America #153 in September 1972, several years after Rick Jones had been Bucky. Monroe eventually leaves the role behind and becomes Nomad, a title that once also belonged to Steve Rogers.
Battlestar
Battlestar was briefly Bucky in the 80s when John Walker became Captain America (he later became the U.S. Agent). Lemar Hoskins was actually a member of the BUCkies, or Bold Urban Commandos, a squad of wrestlers who served as sidekicks more or less to Walker when he was initially the Super-Patriot.
Complaints from fans and legendary comic book writer Dwayne McDuffie prompted writer Mark Gruenwald to change Hoskins' name, as the word 'buck' had unfortunate connotations for African-American men going back to the Civil War. Gruenwald changed the name to Battlestar beginning with Captain America #341.
