The best detail is the Dreepy on top of Mews head, which appears to be quite relaxed as it travels in style on top of the mythical Pokemon, mimicking how Dreepy often sit on Drakloak
This can be any rare or mythic rare in the main set, which is not a legendary creature or planeswalker
Every time someone asked about print differences, the blanket anwer was that there wouldnt be print differences

[1] Bug Weak against : Fire, Flying, Rock Strong against : Grass, Dark, Psychic Dark Weak against : Bug, Fairy, Fighting Strong against : Ghost, Psychic Dragon Weak against : Dragon, Fairy, Ice Strong against : Dragon Electric Weak against : Ground Strong against : Flying, Water Fairy Weak against : Poison, Steel Strong against : Fighting, Dark, Dragon Fighting Weak against : Fairy, Flying, Psychic Strong against : Dark, Ice, Normal, Rock, Steel Fire Weak against : Ground, Rock, Water Strong against : Bug, Grass, Ice, Steel Flying Weak against : Electric, Ice, Rock Strong against : Bug, Fighting, Grass Ghost Weak against : Dark, Ghost Strong against : Ghost, Psychic Grass Weak against : Bug, Fire, Flying, Ice, Poison Strong against : Ground, Rock, Water Ground Weak against : Grass, Ice, Water Strong against : Electric, Fire, Poison, Rock, Steel Ice Weak against : Fighting, Fire, Rock, Steel Strong against : Dragon, Flying, Grass, Ground Normal Weak against : Fighting Strong against : None Poison Weak against : Ground, Psychic Strong against : Fairy, Grass Psychic Weak against : Bug, Dark, Ghost Strong against : Fighting, Poison Rock Weak against : Fighting, Grass, Ground, Steel, Water Strong against : Bug, Fire, Flying, Ice Steel Weak against : Fighting, Fire, Ground Strong against : Fairy, Ice, Rock Water Weak against : Electric, Grass Strong against : Fire, Ground, Rock Practice is the best way to learn and remember all of the different types strengths and weaknesses

"B-Buster" adds "Z-Metal Tank" to hand
Leader Parallels show up in roughly 1 in 6 boxes, and each box guarantees 23 Super Rare cards