To put it simply, every time you open a pack theres a chance that one (or more) of the cards will be a wildcard
The original starter trio, Venusaur, Charizard and Blastoise were available as holographic cards in the set
Gift of Immortality is the source of many a repeatable combo, and Squee, the Immortal is even harder to get rid of than Reassembling Skeleton
Sometimes when we want to test something, we don't leave it to chance
Nothing depicted on cards from AFR is canon in the Magic universe
Demonic Tutor Perhaps the best tutor card in all of Magic: The Gathering, Demonic Tutor is a sorcery and costs two mana, but it lets you fetch any card you need and use it right away