One of those will be Transformers: Robots in Disguise #0, with the following solicit:
Transformers: Robots in Disguise #0—FCBD 2015 EDITION
IDW Publishing
(W) John Barber, Tom Scioli (A) Priscilla Tramontano, Scioli
(CA) Priscilla Tramontano
Optimus Prime is gone — and Decepticons are on the loose! It’s up to Bumblebee and an elite crew of Autobots to track them down before their rampage spreads across Earth! Transformers comics have never been hotter, and the excitement spreads to this all-original comic inspired by the all-new animated series! Plus: previews of IDW and Hasbro unbelievable publishing slate for 2015, including an exclusive Transformers vs. G.I. Joe strip!
32pgs, FC | FREE
It being part of the 12 Gold comics means that any comic book store hosting Free Comic Book day will have some to offer for free (Gold are usually ordered in greater quantities than silver). There will be a total of 50 free comics offered this year at Free Comic Book day.