Full Series Underworld Organizations In Rebels (Spoilers)

The Black Sun has already been mentioned in Rebels and had a big part to play in The Clone Wars with Darth Maul's Shadow Collective. There is a ton of possibilities for Rebels to explore the underworld and criminal organizations across the galaxy. Besides the remaining characters and groups from The Clone Wars (Black Sun, Death Watch, Pykes, Hutt Clans, Shadow Collective, Hondo, Cad Bane, Embo, etc), Rebels is also the time of many new organizations and people like Ketsu Onyo, Vizago and Azmorigan. Also if anyone remembers the amazing game Empire At War, the featured criminal/mercenary organization from the game is canon still.
http://starwars.wikia.com/wiki/Zann_Consortium
I think Rebels would be a great place to not only look more into organizations like the Black Sun, but also explore previously expanded upon groups like the Zann Consortium and see the growing careers of bounty hunters like Boba Fett. Season 2 definitely won't have anything surrounding this unless

Spoiler

Darth Maul is still using Death Watch/Shadow Collective as a power base

but I feel it could have presence in Season 3.