Thousand Waves: Ground, Base Power 90, 100 Accuracy, Physical Attack. The user attacks with a wave that crawls along the ground. Those hit can't flee from battle.
Thousand Arrows: Ground, Base Power 90, 100 Accuracy, Physical Attack. This move also hits opposing Pokémon that are in the air. Those Pokémon are knocked down to the ground.
Something to note: Land's Wrath is also a Ground type physical attack with 90 base power. Could these be the signature moves of Zygarde's form (or forms)? Seems pretty likely to me.
The effects of the moves do sound like they will be really good moves too (except their names are a bit... strange).
Thousand Arrows - AttackDex - Serebii.net
Thousand Waves - AttackDex - Serebii.net