Columbia Pictures (Sony Pictures) is in control of two properties, all things Spider-Man and Ghost Rider. Last appearances of both characters was in 2007, which can explain the seemingly random development updates for a Venom solo project, Spider-Man 4 and Ghost Rider 2. If Columbia has any interest, they can take Black Cat or Carnage and introduce them in the next film; the same applies to Blackheart, Abigor, Wallow and Gressil. As a general rule, any time a studio introduces a comic book character, they have the rights to produce a spin-off or include that character in a sequel of some fashion.
So Morbius, who Spider-Man director Sam Raimi has said to be interested in interpreting, may have some problems if the character isnt cleared with New Line Cinema.
If Columbia Pictures wanted to be a little ballsy, they could go after the entire Blade package and shoot Midnight Sonsthe fictional team of Ghost Rider, Johnny Blaze, Blade, Hannibal King, Morbius and Doctor Strange. Wait
then again, should another studio (thats not Marvel) be in charge of a project like that? Never mind.
Marvel also has regained the rights to Luke Cage from Sony Pictures, so the possibility of a Heroes for Hire movie with him and Iron Fist is not out of the question. Universal has the rights to Namor, but they may be willing to let it revert back to Marvel in exchange for distribution rights.