Here's what Adult Swim has rights to:
Bleach (and two Bleach movies, Memories of Nobody and DiamondDust Rebellion . . . it is not confirmed whether they have the 3rd movie, Fade to Black)
Fullmetal Alchemist (presumably)
Fullmetal Alchemist: Brotherhood (just renewed)
Durarara!! (looks like they have the rights for another year, it's just off the air)
Big O Season 2
Ghost in the Shell: Stand Alone Complex (both seasons)
They recently lost the rights to Kekkaishi.
That's all they have. As you can see even with the new shows their backlog is kinda exhausted at this point, and even if they still have the rights to the original Fullmetal Alchemist, they're not going to run it as long as they're continuing to run Brotherhood.
They may have another show waiting in the wings to begin airing when Deadman finishes its premiere run but there's nothing confirming they do or don't. Same with the possibility they may have a Toonami or Adult Swim classic waiting to make a return. There's a possibility, but zero confirmation or evidence.
There's a million ways to hush my voice
And a million ways to kill my thoughts
Maybe I'm all that you fear
I'm a stargazer
My eyes see differently - Blood Stain Child; "Stargazer"