well people people want to now which mega moves there are and i got a list for you from all the people who learns one and how to obtain it.
megaton head: you can teach him at everyone but i recomend mark-you can get it in cloister after you beaten them-if you want other people learn megaton head you need to go to the old man at cloister and then you can teach him to everybody.
the earth: mark learns it in the final match against genises. fireballstorm: 3 people learn it axel when you do the match against advanced epsilon syon blaze learns it at level 45 nelly learns it at level 80. legendary wolf: shawn learns at the match against the robot guards and canon evans learns it at level 45. god break: aphrodite learns it at level 50 its a powerfull move and its the only move actually you see in inazuma eleven 3. fist of justice: mark learns it in the match against advanced epsilon and silvia learns it at level 80. mugen the hand: darren learns it in the final match against genises when they use supernova.
oh yes i forgot some moves xd. emperor penguin n1:sakuma will learn it at level 45 i believe. beast fang; you can buy it at new raimon where mr veteran stands but you can get it also for genda at level 45 i believe. infinite wall: you can buy it at raimon where mr veteran stands but the goalkeeper from farm learns it too at level 50.