Not entirely certain why Marvel's going in these directions, but it's definitely a strange list:
Black Panther. The only one that's not a deep dig. Black Panther's been a big rumor for quite a while, so it's only a surprise to see it maybe, possibly, actually getting made and released. Maybe we can even get it out in time for him to be in Avengers 2.
Guardians of the Galaxy. All but confirmed, it's set to be announced at San Diego Comic-Con next month. Been rumored since last year, and with their recent return in a storyline featuring the big mystery villain from the Avengers film...it's a safe bet they're on the way (now to wonder who's going to be on the team).
Big Hero 6. The first Disney-animated Marvel film. Love the team, but no idea why they've picked them. And the big question is whether Silver Samurai and Sunfire will be in it, since both are X-Men properties, which Fox currently has the rights to (plus Silver Samurai's rumored to be the Wolverine 2 villain).
Human Fly. Not the Spider-Man villain (for the...two people who know who THAT even is). This is the far more obscure hero based on a real person who briefly had his own series in the 70s (or was it 80s?). Looks to be a low-budget indie film.
There's also Ant-Man. Still being slowly developed, but coming along nonetheless. I mean, hey, there's a script now. And some test footage. That's something. Still trying to figure out Human Fly, though...