Batman is called the sole guardian of Gotham City. He usually has a prickly exterior that's hard to imagine working with. This is clearly seen in trailers for the upcoming The Batman. He's a terrifying presence to Gotham's criminals, and he popularized sidekicks through the "Dynamic Duo" with the first Robin, Dick Grayson.
Robin spiraled out into the Batman Family, a crime-fighting team that includes at least three members. Over time, this sullen character gained a support group. And surprisingly, it worked. Batman absolutely could be a team player. It's adapted as much as Batman's solo adventures. Teams are as crucial as Batman's gadgets, and there's a lot of both.
Sons of Batman
When it comes to iconic works that have not aged well, one thinks of Frank Miller's comic books and Batman history. The Sons of Batman are emblematic of this aging problem. Originally they were Mutants; gangsters Batman fight at the beginning of The Dark Knight Returns. After their leader's defeat, they become non-violent Batman followers. The finale of Returns even shows Batman with them underground.
By the time of the third Dark Knight story, they're now "Batboys," an attack force Batman sends out at his discretion. Their concept eroded; from reformed criminals into a pseudo death squad. They're not a team and more like a private army. Definitely not premiere Batman team, despite debuting in a celebrated story. Formerly formidable, they've decayed over time.
S.H.I.E.L.D.
Surprisingly, Marvel's espionage organization is valid among Batman's teams. In the mid-nineties, DC and Marvel formed a temporary crossover label called Amalgam Comics. Amalgam produced one-shots based on cross-publisher character fusions, including Bruce Wayne: Agent of SHIELD. Bruce isn't Batman in this universe, instead, he is SHIELD's director.
Admittedly, saying Batman's in SHIELD is misleading. But Bruce still leads a squadron with Bat iconography. In the mold of other teams, Bruce leads misfits against huge odds and faces tragedy. As was common for Amalgam, characters died often, painting a bleak world picture. But this Bruce does achieve something that he never could in prime DC; defeat the man who killed his parents.
Mystery Analysts of Gotham City
When first debuted, the Mystery Analysts of Gotham City were as dry as their name. It was civilian mystery enthusiasts led by Jim Gordon and Batman. Basically a fraternal club, this group got together to just discuss mysteries. The most noteworthy thing was that Clark Kent had membership.
However, they were upgraded in Scooby-Doo & Batman: The Brave and the Bold. When Batman: The Brave and the Bold was on air, it resurrected sillier concepts with new flair. This animated film wasn't different; the membership now contained superstars like Martian Manhunter. Batman also crossed over with Mystery Inc, lending cartoon pedigree. This upgrade saved the Analysts from mediocrity among Batman's team history.
Justice League International
Batman can be the protagonist, the lancer, or a supporting character easily. But one role he's often in is that of the comic foil. It's a common trope; a character so serious that they're both the straight and funny man. That's Batman's role in Justice League International.
Those unfamiliar with this branch might find this weird. However, this was a comedic take on the team. There were still stakes and action, but International had Oreo-obsessed Martian Manhunter, Booster Gold running scams, and Guy Gardner, described as a parody of American masculinity. Makes fans wonder how Batman put up with the shenanigans. But the group was beloved, introducing character arcs that continued for decades.
Outsiders
Outsiders were founded by Batman, with a mixed presence over the years. Membership included Metamorpho and Katana, but Batman familiars like Nightwing would occasionally appear. They're also a staple of Black Lightning's career, appearing in his Arrowverse TV show. Batman and Lightning's leadership carried the Outsiders through rocky places.
However, the team's C-list roster made it hard to find an identity. Somewhat fitting considering their name. Outsiders had on-again-off-again publishing history, and many different incarnations. Sometimes typical superheroes, sometimes a black-ops strike force. Presently, they're a secret team. Their biggest impact was establishing Batman as caring about social outcasts. This philanthropic bend is key to Batman.
Justice Society of America
The Justice Society of America is the original superhero team. Batman was merely an occasional member. Later versions gave him full membership, but they didn't need him. This team's street-level roster also had The Spectre, thought of as DCs second most powerful character.
What can't be understated was the Society's impact on the genre. These characters coming together was a big deal. And the team codified many traditions industry-wide. The team's roster also contained prototypes of future DC superstars. Golden Age versions of Green Lantern, Flash, Atom, and Black Canary were all on the team, and endured with Silver Age reboots. The Society stands as a piece of comics history.
Batman Inc/Batmen of All Nations
These organizations have been condensed, as they're very similar. The Batman of All Nations were vigilantes from the world over inspired by Batman. It contained multinational Batmen, like an English Knight, an Australian ranger, and "Bat-Hombre." Fighting with Batman's guidance, they all had similar MOs.
Batman Inc was less team, more initiative. Using his fortune, Bruce financed vigilantes worldwide, including most aforementioned characters. Batman always used charity, but Batman Inc was a new level. This extended Batman's crusade to the entire world. This declared Batman's mission didn't stop at Gotham, extending to all communities. This showed an unexpected, lesser-known side of Bruce Wayne; humanitarianism that exists behind the fear-mongering.
The Lantern Corps
Once publishers decided on shared universes, originally standalone concepts began to crossover. As such, Batman tangled with all DC cosmologies, including the Lantern Corps. He's been a White and Black Lantern during their respective events. He's also been a Yellow Lantern, which makes sense given they both inflict fear.
His most extensive experience is with the Green Lanterns. He's borrowed rings, but in alternate timelines, it's his and he uses it to eliminate crime. Green Lantern ring wielders are incredibly powerful, as any DC fan knows, using willpower to do anything. Hal Jordon, the most famous Lantern, affected changes universe-wide with his. Bats used Hal's ring to fight villains like Darkseid, who's cosmic-level powerful. While Batman's membership is temporary, there's no doubt that the corps let no evil escape their sight.
Batman Family
This is the team that is quintessentially Batman's. Evolved from the Dynamic Duo, the Bat Family's collection of experts trained by Batman have been keeping Gotham relatively safe for decades. The Bat Family has many important members like the classic Robin and Catwoman, but also obscure characters like Gotham Girl. It even has reformed villains like Clayface and Harley Quinn.
It's never dull, as Batman's paranoia means that drama is everywhere. This family is turbulent and conflict-prone. When you have Batman leading and members like Red Hood and Harley, it's inevitable that conflict arises. Despite that, they're compassionate and competent. Reformed villains are allowed to join, and its scope (including alliances) means that multiple districts can be covered simultaneously. The Family may brood, but they're elites that never stop fighting. That makes them second to only perhaps the greatest superhero team.
Justice League of America
The premiere DC superhero team is the Justice League. The all-stars Batman, Superman, Wonder Woman, Flash, Green Lantern, Martian Manhunter, and Aquaman are classic and the membership is always growing. Members of all other teams mentioned have been on the League at some point. Batman's in the group's top three, taking the role of the number two to Superman. So Batman is always important in Justice League stories.
The Justice League has many versions, not just International. Justice Leagues 3000, Dark, Europe, and more have appeared over the years. Different branches serve different functions, and fight crime and support people in unique situations. Also, despite showing up on film only recently, the League's a big part of bringing DC mainstream. Whether Super Friends or Justice League Unlimited, the Justice League has popular adaptations. And DC's Namesake, Batman, serves as ambassador. Batman and the Justice League introduced the world to stories and mythologies seventy years dense, and that's what made them the best.