Reclamation Sage is a classic ETB Naturalize effect to get rid of enchantments or destroy artifacts, and has the elf subtype, which can be relevant in elf typal decks going forward, or even in the sideboard of green decks in general
Otherwise, it can get out of hand pretty quickly by assembling combos around Stasis, Solitary Confinement, and Necropotence, among others
The rewardconsumption into more biofuel for the Hive Fleet
Like infect, mill is loathed by many players, even though its really just as viable of a strategy as any other and often backfires (most decks benefit from having more cards in their graveyard)
Kamigawa: Neon Dynasty
This makes up only one of the Power Nine, a renowned group of cards widely considered the most expensive and influential in the games history