Cut content

Like in almost every game Pokemon Sun and Moon also has unused content that never made it into the game. Here are some of the key things that never made it in or that could down the line.

Unused Mega Stones

Aggronite
Altarinite
Ampharosite
Audinite
Banetite
Beedrillite
Blazikenite
Cameruptite
Diancite
Galladite
Gardevoirite
Heracronite
Houndoomite
Latiasite
Latiosite
Lopunite
Manectricite
Mawilite
Medichamite
Mewtwonite X
Mewtwonite Y
Pidgeotite
Steelixite
Sceptilite
Swampertite
Tyranitarite

Unobtainable Z-Crystals and Z-Moves

Pikashunium Z Ash-Pikachu Thunderbolt 10,000,000 Volt Thunderbolt Electric Special 195
Mewnium Z Mew Psychic Genesis Supernova Psychic Special 185
Marshadownium Z Marshadow Spectral Thief Soul-Stealing 7-Star Strike Ghost Physical 195

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Full list of cut content here

To be honest I think Gamefreak will make players buy Stars if they want all the mega stones and hidden abilities. As for the the Pokemon and Z moves I think they will be handled much like the Gen 6 movie trio where they where released near the time the set movie came out. So this could point towards another movie with that other Ash and then one true Gen 7 movie with the anime's Ash.

Nothing really that game changing it looks like, just some specific goodies for certain ones. Interesting the Ash Pikachu though, must completely break the game by having his moves super effective on every type like in the show.