Understanding how they work will quickly catapult you into the upper tiers of the game
Each booster includes Rares and/or Mythics, shiny foils, special alt-border cards, and more
I have a separate article, Imation Matchprint Proofing Prints and why Im No Longer Interested, which goes into more detail about what these are and how these came to be, and - as its title implies - why Im not interested in them for my own collection
Instant speed burst card draw (including permanents who requires most of their mana be paid in the form of an activated ability), which can draw at least 3 cards for at most X-1 mana, where X is twice the number of cards that they draw
Nyx Lotus in a mono (or sometimes two) color deck can tap for at least three mana, and should it stick around, it will probably help you keep casting your Commander for the rest of the game
Eventually, Karn created Argentum, a plane made entirely of metal