yugioh machine king deck (FMR) Perfect Machine King - Yugipedia

Unlimited, 1993: $73,161 You knew the top three would be the first three releases, didnt you

My guess is that Amulet of Safekeeping is R&Ds attempt to try and answer the question of how to ensure that Modern players can sideboard against multiple strategies at once so that your progression though a large Modern tournament is less matchup dependent

Looking through my own list of decks, for example, my Sigarda, Host of HeronsSigarda, Host of Herons enchantress deck has zero artifacts, and thus zero mana rocks, instead electing to run enchantment-based ramp like OvergrowthOvergrowth and Wild GrowthWild Growth

Still, theres always room for more dual lands in Standard