In Magic: the Gathering (MTG), “best boots” refers to a strategy that involves playing creatures that have abilities that restrict what your opponents can cast. These creatures are often referred to as “bootlegs” due to their ability to prevent your opponents from playing certain spells or abilities by “putting boots on” them.
Best boots strategies are often used in combination with other control-oriented strategies, such as countermagic and removal spells. This can make it very difficult for your opponents to develop their board state and win the game.