The first place I wanted to head was changeling support
Invasion block was all about gold, its Constructed decks were full of gold, and its drafts had players first-picking common mana fixing like Harrow and Fertile Ground over everything but a few rare bombs
It's actually two cards, that combine to form a single card with the standard M:TG monster, representing you summoning a 99/99 Big Furry Monster that also requires you to pay a frick-ton of black mana, and can only exist if both card sits no the board, because it's such a big furry giant-thing
While burn isn't nearly as popular in Commander as other constructed formats, quality burn commanders continue to be released year after year
For example, if you've drawn two cards this turn, Niko will deal 4 damage to the target tapped creature
Its companion restriction reshaped deckbuilding across formats to the point where its influence eventually led to bans in competitive environments like Modern and Pioneer