There are MTG cards with double strike. According to the Internet, introduced with Legions and last used in Evergreen. I don't know how long that was. I remember seeing it back when I was playing, and the cards do look older than the newer ones. They should bring it back if it's not been brought back in a while. I think I had a card with double strike and flanking on it, or maybe that was an enchantment that gave that. I need to go through my decks again.