They are all colorless because Mishras Workshop or Ancient Tomb is just too good and there are enough crazy ramp lands in the older formats to support a deck like that
On January 27, 2021, a "Gem Mint 10 grade" was sold for $511,100
Green and red also have good ways to buff creatures, so you can play something like a Giant Growth on your creature before combat then double its power again
Also, this sweeps graveyard too
Youre looking at a nice 12/12 for 4 once those counters are removed
Making Magic cheaper and more accessible to a wider range of players is a battle worth fighting, but buying, selling, and supporting counterfeit cards simply isn't the right way to fight it