The DCTV Multiverse came together in the epic "Crisis on Infinite Earths" as the Anti-Monitor threatened to consume the realities of all of DC's adaptations on television and film. While the various Arrowverse worlds now stand merged together on Earth-Prime, Oliver Queen heroically sacrificed himself to use the Spectre Force to secretly restore the rest of the DCTV Multiverse as seen in a closing montage with many programs, from DC Universe's Doom Patrol to the upcoming Stargirl television series, all alive and well once again to carry out their own new adventures. And while the Arrowverse heroes are completely unaware that the multiverse still exists beyond their new reality, it would do well for the shared television universe to venture into the multiverse once again for new crossovers and team-ups.
Team Flash carried out its own extensive investigation after realizing that reality had changed following the "Crisis," with Supergirl and Black Lightning's Earths now added to their own while history had been revised. Their determination concluded that many of the alternate Earths simply no longer existed, including Jay Garrick's Earth-3 and Jesse Quick's Earth-2. Batwoman had similarly learned that her sister Beth Kane's doppelgänger had arrived on Earth-Prime after her own world died, leading the heroes to collectively assume that the multiverse had indeed come to an end during "Crisis."
With so many fan-favorite superhero properties existing outside of the Arrowverse, not having them appear either in their own world or on Earth-Prime would be a tremendous waste of storytelling potential. While the Arrowverse continues to expand with planned new shows including Superman & Lois and Green Arrow & the Canaries, there is a joy of seeing team-ups with established series. It's what made the team-up between the Flash and Supergirl particularly memorable before the latter television series moved from CBS to The CW to officially join the Arrowverse.
John Constantine perhaps best epitomizes how successful, cross-platform crossovers can further enrich the Arrowverse, with his growing prominence. Originally starring in his own short-lived television series on Fox, Constantine made a surprise guest appearance during Season 4 of Arrow to help the team reunite Sara Lance's soul with her newly resurrected body. For the next several years, Constantine would appear infrequently before officially joining the cast of Legends of Tomorrow to help the time-traveling heroes take on supernatural threats. And Constantine himself would come full circle with his own surprise team-up by Lucifer during "Crisis," with the pair alluding to having known each other before the crossover.
At this point, there is an expectation that characters from the various Arrowverse shows will appear across the network's shared television universe, even beyond the annual crossover events. Sara has often appeared in Star City outside of her duties on board the Waverider while Cisco Ramon and Felicity Smoak have similarly exchanged spots to lend support while visiting their superhero counterparts. While it's still cool to see this cross-pollination between the Arrowverse, it's the big surprise appearances that really feel special in crossovers now -- even something as brief as Earth-90's Flash appearing during the "Elseworlds" crossover -- this distinction is what made "Crisis on Infinite Earths" so much fun.
As for what shows that would feasibly make the most sense to crossover with the Arrowverse, Stargirl actor Brec Bassinger recently revealed that there had been early talks for her character to appear on an episode of The Flash. While this plan was dropped in favor of delivering a solidly standalone inaugural season for the upcoming DC Universe series, the possibility remains as does the apparent willingness for a DCU original series that more firmly become integrated into the Arrowverse than the more mature Titans or Doom Patrol -- and sign that WarnerMedia and DC Entertainment remain interested in blending programming across its various distribution platforms instead of rigidly confining them.
While The CW and Arrowverse shouldn't attempt to stage a crossover at the same ambitious scale and scope as "Crisis on Infinite Earths" anytime soon, that doesn't mean it should forego new adventures in the multiverse altogether. Just as the DC Multiverse was restored for new stories in the comic book source material, so should the DCTV Multiverse be allowed to include the Arrowverse heroes as it moves beyond "Crisis." And with talks already on the table for potential crossovers beyond The CW's programming and the positive response to the recent crossover, it really feels like it is only a matter of time before the heroes of the Arrowverse discover the multiverse has indeed been restored just in time for new adventures separate from Earth-Prime.
"Crisis on Infinite Earths" is available to stream in its entirety on The CW App.