Chaos Control was memorable for how it signalled a shift towards greater strategy and the existence of defined formats seen in the modern game
at some point, somebody who has one of the promos will want to sell them, so you can find listings on sites like eBay and TCGplayer
Three are Esper (white, blue, and black), one is Grixis (blue, black, and red), one is Jund (black, red, and green), three are Mardu (white, black, and red), one is Abzan (white, black, and green), two are Sultai (blue, black, and green), and one uses all five colours.
Getting to take advantage of an extra 9 board wide damage a turn just for playing aggressively is really easy to leverage in a lot of decks, and once people start losing enough life they have to lose their cards
One box contains 30 packs