Krark, the Thumbless

Cantrips are spells with a draw effect on them. Cantrip decks are often instant and sorcery spell slinger decks and aim to cast as many cantrips as possible and creating value from the cast triggers.

The ways to discard are plenty: cycling, rummaging, end steps discard phase, to name a few. Discard decks are built around triggers from discarding, like madness and synergizes well with reanimating.

Combo decks are control heavy decks, running a heavy amount of card draw or tutors. If the decks get to assemble the combo pieces the game often ends in an infinite combo.

Burn is reds primary mechanics. Red can deal massive amounts of damage to single target or deal multiple amounts of single damage to multiple targets. Burn decks aim to win with massive outbursts of big, uncounterable and unpreventable damage to opponents (and sometimes the burn player itself).