Pokemon Sun and Moon is having a big Mega Stone Mystery Gift event. All of the codes are below featuring codes for Steelix, Sceptile, and Mewtwo.
The Mystery Gift Code is: MATSUBUSA
Use this to get Sceptilite, Blazikenite, Swamperite, Cameruptite, and Banettite.
The Mystery Gift Code is: AZUL
Use this to get Pidgeotite, Steelixite, Heracrossit, and Houndoomite.
The Mystery Gift Code is: INTIMIDATE
Pokemon.com released more Mystery Gift Codes for Mawlite, Beedrillite, Audinite, and Medichamite.
The Mystery Gift Code is: M2DESCENT In March 2017, Pokemon.com released a Mystery Gift Code for both Mewtwonite X and Mewtwonite Y, used to Mega Evolve Mewtwo into Mega Mewtwo X and Mega Mewtwo Y.