(A regular Art card can be found in 30% of packs and a foil-stamped Signature Art card can be found in 5% of packs.) Every pack Includes 14 cards of rarity Rare or higher and 36 Uncommon, 69 Common, and 1 Land cards
Three cards will also appear next to your name in the trading menu, giving your friends an excellent idea of what you're looking forward to
That said, they shuffle up just the same, and you can use a few of these mixed into a deck with regular cards without worrying about marking your deck
#2 As long as the alter doesn't cover any relevant information or alter the art beyond recognition, you should be ok
Necrogoyf is actually more interesting though since it gets BIG, essentially an upgraded Mortivore that also enables discard / madness outlets AND comes with madness to boot
However, not just Planeswalkers but all cards have strong character imagery