Star Wars Cassian Andor: 10 Rebels Characters Who Need To Appear
9. Hera Syndulla
Unlike some of her companions in the Ghost Crew, who were focused on Jedi business, Hera was a die-hard Rebel. She's even mentioned in Rogue One twice, though the second time it's a tiny cameo, where The Ghost can be seen among other ships in the Battle of Scarif. However her name can be heard in the Rebel Base of Yavin IV as well, as she's being called through the speakers.
Live-action Star Wars has lacked aliens who were more than just background characters, and introducing Hera in this show could remedy that massively.
Having her know Cassian would also add an interesting narrative angle to the Rebels as a whole, since we know that Hera survives Scarif and, ultimately, the Battle of Endor.