Usually, cards go by one of a few select levels: Common Uncommon Rare Super Rare The Super Rare category typically has the shiny foil you should be looking for, though you can take a look at the lower-righthand side of the card to make sure
There are 20 mythics in the set, and all of them have at least one variant, either Showcase or Extended Art, and no additional ones past that
The contents are as follows: Common (6) Uncommon (3) Rare, Super Rare, or Legendary (2) Foil (1) Each pack comes with a foil card, which can be of any rarity
Travis Stanley Yoshimaru, Ever Faithful is definitely my favorite commander of the year
PPC - Deletion Sphere 160+ You may discard up to 2 Energy from your Benched Pokmon
Basically, they make it so that both spells and abilities that your opponents control cost an extra two mana to cast or activate if they target a Merfolk you control