Trish 'Patsy' Walker is Jessica's adopted sister, basically her only true friend in the world (until Mr Cage shows up, anyway), and a big part of the mission to take down Kilgrave. However, could there be even more to her? If the show does go down a more superheroic route, then you'd have to image she will become some variation of Hellcat, which is the alter-ego of Patsy Walker in the comics. It may not actually give her all of the powers that come with that - force fields and detecting mystical phenomena - but it wouldn't be too much of a stretch to see her become a crime-fighter using the moniker and maybe even some version of the costume (no matter how much Jessica scoffs). There is already basis for this, as Trish has trained in fighting quite a lot, and when she takes the red pill to fight Simpson she gets into some pretty awesome fight scenes, so a progression from that (only without the need for drugs) would be good to see.