It can depend on rarity, popularity in competitive formats, or simply how striking the artwork is
Another expensive but very valuable card is Robin Hood - Timely Contestant as he has a summoning cost of 9 Ink
Iron Bundle [Paradox Rift] works like a pseudo-Escape Rope [Battle Styles] to force your opponent to send up one of their Pokemon from the Bench, and then discards itself afterwards
Legendary Creature - Human Knight Chatterfang, Squirrel General Forestwalk (This creature can't be blocked as long as defending player controls a Forest.) If one or more tokens would be created under your control, those tokens plus that many 1/1 green Squirrel creature tokens are created instead
Anyone whos had the misfortune of playing against Prosper, Tome-Bound will know that Rakdos players can absolutely run away with the game if allowed to rack up too much Treasure, and Decadent Dragon is the perfect enabler for most red/black Treasure strategies
Once the exiled creature returns, it's considered a new object with no relation to the object that it was