mtg booster box theros Beyond Death Bundle There are three Planeswalkers in the set Theros Booster Box - Magic:

Sphinx of Clear Skies was first released in the set Dominaria United, illustrated by Valera Lutfullina

Its certainly slow, but its worthwhile given that activating it triggers all your sacrifice payoffs

uses a system of monster summoning, tributes, traps, spells and all sorts of other weird and wonderful effects to make reducing your foes life points to zero as interesting (and as difficult) as possible, so its good to know that by default the game requires your confirmation to proceed when an opponent pulls off a complicated discard/special summon/spell combo

5 Mana spells WUBRG to me

Chances are good that at least a couple of them appealed to your deckbuilding interests, but with a volume this large, its entirely possible you might have overlooked some cool ones along the way

If something costs an outrageous amount of money, don't bite - it's a cheeky reseller taking advantage of scarcity