Arcane Signet is a solid source of ramp and fixing
Moving forward, opportunities related to Modern are much more likely to involve three specific categories of targets: High demand recovering reprints, eg: LoTV, Tarmogoyf, Snapcaster Mage, Cavern of Souls Recent reprint dodgers, eg: Ancestral Visions, Inkmoth Nexus, Engineered Explosives, Grove of the Burnwillows, Mishras Bauble Newly unlocked/underestimated cards, eg: Rite of Passage, Deaths Shadow, Amulet of Vigor, etc
Blasphemous Edict costs five mana and has each player sacrifice 13 creatures of their choosing
The other factor with Natural Order is that when you have enough cheap green creatures in your deck to enable it you probably just have enough mana to cast the things you would want to Order up
Instants were a type of card that had a good amount of change done to them in Revised