These Oil counters do different things depending on the card, but if youre in those colors, you should be looking to spread Oil counters to as many of your cards as possible to maximise the effect they have on the game
If youre dying to spread chaos and generally make your competitors have a miserable experience with Lorcana, then emerald cards are the way to go
It's the greatest, so fast you won't even know it happened
For better or worse, it seems that the Final Fantasy MTG set isnt being too bold with its many mechanics
Perhaps the one Ive seen the most and has been sent to me the most was the one I thought of first: Jumbo Cactuar, Swords to Plowshares, Aetherflux Reservoir
Due to how this is worded, even if Gyrus is removed and cast again, the payment of Commander Tax provides additional counters