Fantasy It turns out the original Collectible Card Game, the first entry in a whole new hobby, apparently hasn't been reviewed yet here. TSR getting gobbled up by WotC which in turn got gobbled up by Hasbro, but speaking as one who plays both I see no inherent conflict. And of course, both hobbies survived. So, the basic explanation of the game. They play and tap land cards for mana, allowing them to cast spells.
Spells come in a number of categories.
Creatures are what you summon to battle with your opponent's creatures- if a creature attacks and no opposing creature blocks it, it does damage to your opponent. If an opponent loses all of his 20 life, he's out. Sorceries and Instants have powerful one-shot effects like gaining life or destroying creatures. Rules summary over. The official 'setting' for the game is Dominia, a multiplanar universe, and Dominaria, one of the worlds in that universe, is often the focus.