All 10 SRs have been revealed, but none of the SECs yet.
So far we would bet on 2 of these 3 cards being SEC: Alphamon Ouryuken Mode, Imperialdramon Paladin Mode, and Gulusgammamon.
Alphamon Ouryuken Mode (OM) would be the easy one, having Ouryumon revealed for this set. However, it is still possible for Alphamon OM to be saved for a later set given how Bandai likes to stagger fan favourites. Furthermore, Alphamon OM has almost nothing to do with the theme of this set (being New Hero) so let’s not have our hopes too high.
Imperialdramon Paladin Mode (PM) is our second guess for SEC, based on the fact that this is a Digimon Adventure 02 themed booster, and there is no big protagonist cards yet other than [BT8-032] Imperialdramon Fighter Mode which was revealed very early for this set. There is also no LV7s yet for this set, so Imperialdramon PM could make a good, in-theme SEC.
Our third guess for SEC would be Gulusgammamon, as it would be quite weird for Gammamon to appear in the pack art, and then to have the only “Ghost Game” cards in this set being a Digitama, a LV3 Gammamon, a LV4 Betelgammamon common card, and his tamer Hiro. Gulusgammamon would make a good art, and does not interfere with Gammamon’s digivolution line in the future.