Sableye is amazing in Great League, which I use very often and have just competed a tournament yesterday with it in my team of 6.
It has its pros and cons. Cons being a little bit glassy, and most of the time rely on shield to stay in the field. But the pros is its rather "unknown" position in the meta for most, amazing resistances, and access to shadow claw + power gem/foul play. With Sableye in your team you need to kind of cover its back with the other 2 pokemons.
I had a lot of fun using it myself, to say the least!
