Confirmed Monsters Thus Far:
GOJIRA (Including various other incarnations)
DESTOROYAH (Adult and Aggregate Form)
SPACEGODZILLA -X Rare Card
MOTHRA 1992 (Adult and Larva) X Rare Card
KING GHIDORAH 1991 -X Rare Card
MECHA KING GHIDORAH
KIRYU -X Rare Card
GIGAN GFW MODIFIED
There are 52 Cards total, with an extra 5 cards which are rare.
Check out the promo video and a few of the cards below.