Creature - Elder Dragon Color tag templates(None) Archmage of Runes Instant and sorcery spells you cast cost less to cast
Although its unclear what exact function Roshan, Hidden Magister will have overall, it does seem to be particularly good in a disguise/morph build in an assassins deck so you can get assassin attacking triggers for those face-down creatures
While not the biggest, baddest dude on the plane, Jorn's ability is incredibly powerful if your deck is built around him: whenever he attacks, you untap all snow permanents
Put all creature cards revealed this way into your graveyard, then put the rest on the bottom of your library in a random order
But theyre also good for: Deciding who gets first turn in the match Simulating coin flips for The Gold Saucer (call odds/evens instead of heads/tails) Randomly choosing a card for Sin, Spiras Punishment Tracking the mana in your mana pool (if a card like Esper Terra makes a lot all at once) Representing the numbers (and/or stats) of tokens you create Keeping count of random statistics that your cards care about, like how close you are to transforming Emet-Selch or how many times Sephiroth has triggered this turn Helping you remember important upkeep triggers like Dark Confidant or Seymour Flux (place a die on top of your deck every turn so you cant draw a card without stopping to remember why its there) and plenty more
