If youre looking to maximize your mashups, The Lord of the Rings: Tales of Middle-earth Jumpstart Boosters can be combined with packs from any other Jumpstart product.
There are 3 mythic rare (2.5%) classic comic cards that can appear in this slot
From the hand, among other things: Monster Cards can be Normal Summoned/Set, Pendulum Monsters can be activated in the Pendulum Zone, Spell Cards can be activated, Spell/Trap Cards (except Field Spell Cards) can be Set in the Spell & Trap Zone, and Field Spell Cards can be Set in the Field Zone
Cards are typically 2.5 x 3.5 (63.5 x 88.9 mm), and borders are 1/8th (0.125) of an inch (3.175 mm), meaning the main card area is about 2.25 x 3.25 (57.15 x 76.2 mm)
Due to release in the west on July 18, the Japanese versions of the set are available from this Friday, June 6, and, as is customary in release week, ARs and SARs in the set are being revealed