In fact, this list doesn't include a card that's below $200, which is a remarkable market value considering how young these cards are
According to Mark Rosewater, they did that on purpose for Tarkir: Dragonstorm (because, as of late, the MTG Play Design team tends to avoid flashback on instants)
Doubling Season has been reprinted in Commander Masters and its in the Wilds of Eldraine Enchanting Tales list, so while its still expensive, this year its likely to be as accessible as its been for a long, long time, so pick one up if you can
The listing uses only stock images for a high-value single
The rest of the cards will be put on the bottom of your library in a random order
Whenever Slurrk or another creature you control dies, if it had a +1/+1 counter on it, put a +1/+1 counter on each creature you control that has a +1/+1 counter on it