If for some reason you tried to generate other mana outside your color identity (like if, for example, you were playing Rakdos and gained control of someones Noble Hierarch), it produced colorless instead
Remember, these are guidelines, not rules
Patient buyers sometimes secure The Scarab God for less during lower-traffic auction windows
Modern cards are printed and preserved on a vaster scale than the original sets ever were, so the likelihood that many of them will reach the heights of Base Set Charizard looks slim
Even though it's still mostly creatures (as most Commander decks tend to be), many of those creatures have multiple types, like Solemn Simulacrum, Skola Grovedancer, Nyx Weaver, and Haywire Mite
Best of all is the fact that publisher Wizards of the Coast is coming out swinging with an entire set inspired by Final Fantasy