The Arrowverse has delivered a lot of fan service and has been incredibly dedicated to making sure that the audience is enjoying this run of interconnecting DC TV shows. There have been a few friendships that would have been compelling to see on screen though that never quite came to fruition.
Whether it was because of scheduling conflicts, the lack of a significant part in the Arrowverse, or the complicated nature of the Multiverse itself, some of these potential friends went unsatisfied. While a few of these could still be seen down the line, these loyal sidekicks, iconic heroes, and dastardly villains haven't teamed up in the way fans want quite yet.
Batman And Superman
The World's Greatest is a team that many comic book readers would be very familiar with. In fact, some of the Man of Steel's and the Dark Knight's best stories have come when Batman and Superman are teaming up alongside one another.
Whereas the Arrowverse's version of the Man of Tomorrow has taken on a more prominent role in recent years and is set for his own TV show, the universe's version of Batman has only been seen briefly with Hush taking on the face of Bruce Wayne and in the future timeline of a different Earth. Needless to say, their friendship hasn't been seen on screen.
Supergirl And Batwoman 2
In contrast to this, the Arrowverse did develop a friendship between Kara Danvers and Kate Kane. The two heroines built up a lot of loyalty and trust, especially concerning the availability of the deadly Kryptonite. Kane's disappearance changed all of that.
As audiences continue to learn more about Ryan Wilder, the new Batwoman, many became aware that this version of the vigilante might not get to meet Supergirl herself. The scheduling conflicts of the show means that Kara and Ryan are unfortunately never going to crossover or indeed form a friendship like their predecessors did.
Constantine And Manchester Black
This may seem like an odd crossover, considering the two characters rarely meet one another in the comics, but Manchester Black and John Constantine might be the chaotic friendship that no one realized they needed. For starters, both of course have English backgrounds.
While Black hails from Manchester, Constantine comes from the gritty streets of London. Nationality aside, they have both walked similar paths in the past, although have come to starkly different conclusions. Each is fiery, violent, and in need of redemption; they'd actually make quite a compelling pair.
Green Arrow And Green Lantern
Green Arrow and Green Lantern, that is to say Oliver Queen and Hal Jordan, are as thick as thieves in the comics. It's one of DC's most famous friendships, but the Arrowverse could never see it come to fruition. There was a slight twist on it though.
While Queen and Jordan never even met, nor does Jordan seemingly exist in this universe yet, John Diggle of the Arrowverse actually becomes the Green Lantern. This was a sneaky way to have the Green Arrow and Lantern still form a firm friendship; there's still hope that even in spite of cancellation that perhaps the next Green Arrow could form a relationship with a new Green Lantern.
The Birds Of Prey
The Birds of Prey have appeared in the DCEU which is technically connected to the Arrowverse thanks to the Multiverse itself. There's also a very loose version of the Birds of Prey in this universe, which features the likes of Overwatch, Black Canary, White Canary, and Black Siren.
The core team has never been brought together on screen though. A glaring example of this is the absence of the Huntress during their main team-ups. The character is present in the Arrowverse but not brought into this team properly. It's a shame these friendships couldn't form sufficiently.
Red Hood And Arsenal
The comics have seen Red Hood and Arsenal team up on countless occasions. They had their own comic run together, sharing a title, and have been a part of the Titans and the Outlaws. Each shares a history of being an overlooked sidekick and fall back on violent tendencies.
The Red Hood and Arsenal have both appeared in the Arrowverse, but are separated on different Earths. They have never met nor have they been allowed to form a friendship. Maybe Roy Harper, or even the Thea Queen version of the character, might have been able to put Jason Todd on the right path.
The Rogues
The Rogues are a collection of Flash villains who have worked alongside one another countless times to take on the Scarlet Speedster. Over time they have formed a sort of friendship and while trust might be a stretch there is at least respect amongst them.
The general idea was applied to Captain Cold and Heatwave and then again with the Legends of Tomorrow. However, the proper iteration of the Rogues, including the likes of Cold, Heatwave, Weather Wizard, Golden Glider, Rainbow Raider, Trickster, and Mirror Master never really formed thus leaving a number of potential friendships behind.
Mr. Terrific And Vibe
Mr. Terrific and Vibe actually met each other on a few occasions. Indeed Curtis and Cisco were compared to each other in countless scenes, with each serving as both a tech and science expert and an engineer on their respective teams, alongside suiting up as a hero.
If these two 'nerds' could have been allowed to spend some proper time together on screen though, a proper friendship might have been able to form which may have created the groundwork for an Arrowverse version of the Terrifics; maybe even with the Elongated Man. It's perhaps a missed opportunity to not see these two in action together.
Hawkgirl And Martian Manhunter
Hawkgirl and Martian Manhunter worked alongside each other a number of times, as part of the Justice League and on team-up missions. A friendship started to form between the two, which eventually developed into quite a compelling romance.
In the Arrowverse, while Martian Manhunter is one of the older heroes and a veteran of the crime fighting scene, Hawkgirl only briefly appeared before being written out of her respective show. The pair might have really clicked if they had been allowed to share the screen together.
The Toyman And The Trickster
This is another out there connection but the Toyman and the Trickster were two villains who were actually portrayed in vaguely similar ways in the Arrowverse. One fought against Supergirl while the other found their foe in the Flash.
However, while fans got to see Supergirl and Flash team up with one another over and over again, their villains did not do the same. The quirky personality and shared aesthetic of these villains could have resulted in quite a bizarre friendship.