Double strike is self-explanatory: you deal twice the damage (a creature's power)
A well known fact, from the days before you had to play with sleeves, was also that the first printings of Mirage was far more glossy than other sets (same with some printings of Antiquities), which made Mirage lands sough after by semi-cheaters who wanted to be able to see if the top card of their library was a basic land
Whenever equipped creature deals combat damage to a player, you may cast an instant or sorcery spell from your hand with mana value less than or equal to that damage without paying its mana cost
If you first play a 3/3 creature, your foe may be tempted to use Fatal Push on it (costs less than Go for the Throat), and will have no answer for Roaming Throne
Similar to trading card games such as Magic: The Gathering and Pokmon, Disney Lorcana allows two players to create a custom deck of cards before battling their decks to see who emerges the winner
Mewtwo VSTAR I am not sure about Mewtwo VSTARs impact in the metagame, especially in a post-rotation format, but you can never be too sure with Mewtwo because it has always been one of the strongest Pokmon in the game