Im especially interested in using Herigast, Erupting Nullkite to pay the emerge cost of, say, Void Winnower or Ulamog, the Ceaseless Hunger
For example, Core Set 2019 proved to be the perfect place to design a bunch of cards aimed at Modern
playtesting forms the biggest population of proxy users when it comes to Magic: the Gathering
In addition to this, a big part of the reason these cards were so popular was because the mana in that Standard format was quite bad, to the extent that you were pretty close to wanting Attune with Aether in your decks even before the energy bonus, but once you have the energy bonus you might as well play Harnessed Lightning, which means you may as well play Rogue Refiner to power up your kill spell, and so on
Cori-Steel Cutter also sees play in older formats, specifically in Prowess decks in Pioneer and Modern, so while its price will drop from its $9.00 peak, it wont hit bulk status
But for those of you who want to actually read words, let me lay it down