A set of Madalorian armor which is implied to have been Fett's is seen in Star Wars: Aftermath
From the box, he withdraws a helmet. Pitted and pocked, as if with some kind of acid. But still-- he raps his knuckles on it . The Mandalorians knew how to make armor, didn't they? "Look at this," he says, holding it up. "Mandalorian battle armor"Mandalorian battle armor. Whole box. Complete set, by the looks of it. Been through hell and back. Been through hell and back. I think my boss will appreciate this."
However, this doesn't necessarily mean that Boba Fett is alive, just that his armor somehow made it out of the Sarlacc. (He could have died afterwards.)