Hey there iGeko97,
First of all welcome to PRO and the forums! i hope you enjoy your stay :)
There are only 3 legendary pokemons in this game so far which is Mew, Celebi and Jirachi. I hope these guides will help you with getting your legendaries : Mew , Celebi and Jirachi .
if you want to ask about anything do not hesitate.
I wish you all the best :Angel: