Light of ruin, Thousand Waves, and Thousand Arrows are unreleased attacks that were put in the game but not removed, like the hacked legendaries (Diancie, Volcanion, and Hoopa). LIght of Ruin is the signature move of the Eternal Flower Floette. (AZ's Floette) Thousand Arrows and Thousand Waves are the two of Zygarde's signature moves. (If I'm correct) All of these moves are not obtainable in game without hacks.
Hope I helped!