For eight mana, Archetype of Endurance grants all your creatures, including itself, hexproof, but more importantly, it strips hexproof from your opponents and prevents them from gaining hexproof as long as it's in play
This can go off easily in GW +1/+1 counters and BW lifegain -- gaining counters and drawing cards is the kind of engine that can win you the game
While I will tend to follow the same sorts of rules for building a sealed deck every time (prioritize removal and evasion creatures, about seventeen creatures, seventeen lands, and six spells, try to stay two colors), I also never want to go into battle without some notion of how I intend to win
Whether youre clearing the board or going straight to the face, it offers precision and flexibility