It was manageable, but not intuitive and I could see new players having trouble getting this right
We can leave a box around the Card Name and Mana Cost, and also around the Card Type and Set Symbol (usually on Modern-bordered cards)
The first card that I am considering as a replacement for Greed is Erebos, God of the Dead, since he has the exact same mana cost as Greed, as well as being indestructible, preventing my opponents from gaining life, and potentially being a 5/7 creature, but my only concern is that his activated ability costs 1 more mana than does that of Greed, and that additional cost shall add up, over the course of a game
Reprint Chances: Likely (Whip-Spine Drake) and Unlikely (Lumithread Field, Whetwheel, and Zoetic Cavern) Sliver Cycle Slivers were another creation from Mike Elliott's Astral Ways set
Which is a bizarre enough visual image
This means you can pay these costs with any Basic Energy you want