For more than two decades, potential Pokémon Masters have been traveling through regions of the ever-expanding world to test their skills against powerful trainers atop various themed gyms. Whether you cut your teeth on Red & Blue or you just leapt into the world of Pokémon with Sword & Shield, you likely have a favorite gym leader. While it was difficult to whittle the list of memorable leaders down to 10, these are our favorite gym leaders from across the entire series.