The popularity of these isn't without merit as some of the more powerful reprints and new EDH cards are printed here
The deckbuilding rules are what make it so distinct and foster such incredible diversity
You can read more about these events in the official Magic fiction at www.mtgstory.com
The key to making black-red work is to understand what identity you want to give this "killing machine." Black's selfishness matched with red's hedonism means that Rakdos tends to have a sadistic streak
But green often needs a devotion count for Nykthos, Shrine to Nyx, links in a Birthing Pod chain, or just bodies to mass-pump with Craterhoof Behemoth, so this green card feels like its lacking a bit of a home outside one sort of deck, a self-mill lands recursion/ramp deck
#4 Forge Anew Forge Anew is yet another card with implications for Hammer Time in Modern, but this time it is a bit more obvious