These characters are unlikely to make an appearance on Supergirl’s 100th episode, but it would be fun to see them!
Oliver Queen AKA Green Arrow
Although Oliver’s role in Kara’s life was never as prominent as some of the other heroes’, he’s been the “leader” of most of the crossovers to date—which has been the only time we’ve seen these two together. Even though their Earth-X doppelgangers were evil, it was fun to see a version of Oliver and Kara together and, even as Earth-1/Earth-38 friends, it would have been fun to see them interact more.
However, there isn’t a moment between the two that is important enough to undo what Oliver’s sacrifice (and Stephen Amell’s departure) meant to the Arrowverse. If we’re ever to see Oliver Queen again, it will be in the far future—likely one that Barry messed up by time traveling.
Barry Allen AKA The Flash
Speaking of Barry, some of the best moments since the creation of the Arrowverse have been shared with Kara and Barry on screen together. From the moment they met, back in season one of Supergirl, the chemistry these two share has been absolutely adorable. With these heroes now sharing a home on Earth-Prime, we’ll likely see more of these two together.
Kara meeting Barry back in the first season of Supergirl is monumental. It opened up the multiverse—for Barry, there was more than just Earth-1 and Earth-2. For Kara, it was the first time the idea of a multiverse was introduced. However, with the likelihood of seeing more SuperFlash team-ups in the future, it’s unlikely Barry will head to National City for Supergirl‘s 100th episode.
Maggie Sawyer
The last time we saw Maggie was early in season three. While her and Kara’s sister, Alex Danvers, were in love, they had different opinions on their future with kids—Alex wanted them and Maggie did not.
Even though Maggie also shares a history with Kara, the synopsis makes it feel like we’ll be visiting key moments from Kara’s point of view. They may have shared a few, but likely not any big enough to warrant seeing Maggie Sawyer once more.