Just saw an interesting post on Moviepilot (which is one of the worst, click-baitiest sites I've ever visited) which shows a still when the Knights of Ren Aden standing in the rain.
The theory is that Boba Fett has joined up with the Knights in some capacity. The blown up still does actually show a figure wearing a Mandalorian helmet. Of course, this could be anyone, but what I found interesting is that in the Aftermath story, Boba's armor is recovered and still intact. Take this with a grain of salt but how cool would it be to see Han and Boba run into each other once again.