While Supergirl is expected to deal with any aftermath that Non and Indigo are yet to cause for Earth, she will be expected to encounter more enemies including some that her cousin Superman fights like Doomsday, but she is also expected to meet up and team up with more heroes on her side of the Arrow Multiverse and one of those heroes that Supergirl is to meet and team up with for the yet o be confirmed episode is Barbara Gordon aka Batgirl.
While Batgirl is yet to be confirmed for Supergirl season 2, one villain for her and Supergirl to team up against on Halloween that she and Batman deal with that fits in Supergirl's playing field both on the ground and up in the air as well as being Halloween scary is Man Bat!!
Man Bat is a tough and reckless beast who is truly Dr. Kirk Langstrom who was studying bats and tries to create a serum benefitial for humans but ends up turning himself into a giant bat and loses control. In this form of a giant bat, Langstrom is intensely strong and dangerous, strong enough to take on Supergirl if they do commence getting Batgirl and several other Batman characters to appear in the Arrowverse with a series based on Batman's female sidekick, things are sure to get better as the show is yet to have the character taking place a few years after recovering from the Joker incident that left her in a wheelchair for three years as Oracle.
Then of course there's Silver Banshee who too would fit the Halloween crossover but only if Italia Ricci has the chance to reprise her role for that episode in the fall because right now she will be busy co-starring as one of the main cast members of the upcoming show called Designated Survivor and clearly it might mean that she may not be back to reprise her role as the character until next year in season 2. Still then again depending on whether she and the rest of the crew are able to take some time off from filming more episodes and with Italia herself being able to reprise her role as Siobhan and intends on fighting Supergirl again but as a solo act this time is up to the executive producers in charge on what they have planned so for now Silver Banshee is in the maybe pile. Be sure to catch the season 1 finale of Supergirl and stay tuned for season 2 later this fall.