Here are my favorite picks for anime like Trigun. Keep in mind the list is in no particular order. Enjoy!
Rurouni Kenshin: Meiji Kenkaku Romantan
In the final years of the Bakumatsu era lived a legendary assassin known as Hitokiri Battousai. Feared as a merciless killer, he was unmatched throughout the country, but mysteriously disappeared at the peak of the Japanese Revolution. It has been ten peaceful years since then, but the very mention of Battousai still strikes terror into the hearts of war veterans.
In the future, Japan is a wasteland. In the Great Kantou Desert, scattered humans seek out a living in the hot sand. Among them, a short-statured man they call “Sunabouzu” makes a living as a bounty hunter. Like a demon of the sand, he seems unbeatable. Yet, like all men, he has a particular weakness for the opposite sex…
The background is in the distant future after the destruction brought about by Armageddon. The war between the vampires and the humans continue to persist. In order to protect the humans from the vampires, the Vatican has to rely on other allies to counter the situation. The protagonist, Abel Nightroad, is a traveling priest from the Vatican and a crusnik, a vampire that drinks the blood of vampires. He is a member of the “Ax”, a special operations group led by Cardinal Catherina Sforza. He encounters a young girl called Esther, who decides to go with him to Rome and train at the Vatican. Soon after he meets her, the order of Rozencreuz, led by Abel’s twin, Cain, tries to continue the war so they can rule the world. It’s up to Abel and the AX to try and stop them.
Gun x Sword
Van, a lanky and apathetic swordsman, is on a journey to kill the murderer of his fiancé. The only characteristic he has to go by is that the murderer has a claw for an arm, hence the murderer being referred to as The Claw Man. During his travels, Van happens to pass through the city of Evergreen, which is defending itself from bandits who aim to rob the city of its treasury. It is in this city that Van meets Wendy Garret, a timid young girl who is looking for her kidnapped brother. When the city pleads for Van’s assistance to defend it, he refuses, claiming it has nothing to do with him and thus leaves the city on its own to deal with the peril. Soon after, Van comes across the raiding bandits himself and they eventually tick off the swordsman to a degree where he takes action against them for his own personal vendetta. Surprisingly, Van learns that the bandits had ties with The Claw Man, and in kidnapping Wendy’s brother for a reason they did not disclose. After the bandits are dealt with easily, Van and, much to his chagrin, Wendy continue the journey in search of The Claw Man. Little do they know, however, that The Claw Man is involved with something more atrocious than either could fathom.
Grenadier: Hohoemi no Senshi
Rushuna is a blonde and very beautiful Senshi (gun expert) that travels through the world with one purpose. Which is to make the world a peaceful place by, instead of fighting with weapons, taking away the people’s will to fight by giving them a smile. Although she doesn’t want to fight, she is forced to, and shows amazing gun skills. In this journey she meets Yajirou, a mercenary that uses a sword to fight and joins her on her journey.
Completing every job with ruthless accuracy, Train Heartnet is an infamous assassin with no regard for human life. Donning the moniker “Black Cat” in the underground world, the elite killer works for the powerful secret organization known only as Chronos.
Seihou Bukyou Outlaw Star
Gene Starwind has always dreamed of piloting his own ship out into the vast sea of stars. Unfortunately, not all dreams come true, as he spends his days working odd jobs alongside his partner, James Hawking, on the small planet Sentinel III instead. However, this all takes a turn when the duo takes on a job from Rachel Sweet who, unbeknownst to them, is actually a treasure-hunting outlaw. Tasked with protecting a mysterious girl known as Melfina, the meeting irrevocably changes the pair’s lives as they are sent out into the great unknown aboard the highly advanced ship, Outlaw Star.
Hellsing, an organization specializing in dealing with supernatural threats, is called in to eliminate a vampire that is turning the villagers of Cheddar into ghouls. To put an end to this, the leader of the organization, Sir Integra Fairbrook Wingates Hellsing, dispatches her most formidable asset: a powerful vampire known as Alucard.
In the distant future, where cyborgs and humans struggle to survive after the war which destroyed the world, a being in white suit awakens. His name is Casshern and he remembers nothing of his own past.
Within Thailand is Roanapur, a depraved, crime-ridden city where not even the authorities or churches are untouched by the claws of corruption. A haven for convicts and degenerates alike, the city is notorious for being the center of illegal activities and operations, often fueled by local crime syndicates.