The Punisher, as played by Jon Bernthal, was an obvious choice for his own spin-off series after he stole the show in Daredevil season two. Another supporting character from an existing show who could lead their own series, though, is Jessica Jones’ Trish Walker.
The character usually known as Patsy Walker has a long and unusual history in the comics. Originally the star of a romance comic in the 1940s, she was later introduced into Marvel’s superhero line-up as the Hell’s Kitchen vigilante Hellcat. If this is an avenue Marvel wish to explore, Rachael Taylor has impressed with what she has done so far, so she would no doubt have the skills to carry her own show.
Hellcat also has a lot of supernatural connections in the source material, such as her mother selling her soul to Satan and then eventually marrying Daimon Hellstrom, Satan’s son. This could tie in well with the horror themes of Blade, Ghost Rider and Moon Knight, if they really are coming to Netflix, as well.