With the first series being rather small on robot characters (4 main cast, 2 guest cast), and the second series being shown off at SDCC just having repack/redecos (with two playsets being the only "new" toys)... it didn't look like much was to be expected for the second year of Rescue Bots.
But sneaking out through a dealer listing, and now on the Hasbro instructions archive, we have two new Rescue Bots characters:

Hoist the Tow Bot - a tow truck.
Medix the Doc Bot - an ambulance.

Judging by the extended names (Tow Bot, Doc Bot), I'd be thinking that these might be new cast characters in the cartoon, if it has a second season.

It will be interesting to see what colours they give these toys... will they be classic Gen1 colours for Hoist, and "Ratchet" colours for Medix.


(NOTE - since Rescue Bots have been proven to be part of the TFPrime story-verse, they couldn't have Ratchet as the Doc Bot if they plan on it being in the cartoon).