When they release new games in the series, they often add new Pokemon, and introduce newly discovered evolutions or new artwork for previously discovered Pokemon.
In the case of Pokemon Sun and Moon some of the changes we will be seeing in older Pokemon seem to be called "Alola forms." The ones we know are as follows:
The bad guys are apparently called Team Skull. We also know that there are some new Pokemon like a sandcastle Pokémon, a single fish that can change to a school of fish, and there is also reportedly a new Pokemon called Gumshoos that many say looks like Donald Trump.
Celesteela is a Steel-Flying type, and it was introduced in the Generation 7 games, Pokemon Sun and Pokemon Moon.
The Pokémon Sun and Moon games will be released on November 23rd in Europe and November 18th in the rest of the world.
Pokemon Sun and Pokemon Moon are the newest games that will be for the Nintendo 3DS and Nintendo 2DS systems, you will be starting as a new trainer who had just moved into the Alola region which consists of at least four islands and you will also need to select one of three Starter Pokemon and you will also be in charge of catching Pokemon that can be found in the Alola region and you can also beat the Gym Leaders, the Elite 4 trainers and the Champion.
The Pokémon Sun and Moon games will be released in the United States of America on November 18, exclusively for the Nintendo 3DS family.
Marshadow is a Fighting-Ghost type, and it was introduced in the Generation 7 games, Pokemon Sun and Pokemon Moon. Marshadow is a Mythical Pokemon.
Both Alolan Meowth and Persian share the Dark-typing in Pokémon Sun and Moon.
Xurkitree is an Electric type, and it was introduced in the Generation 7 games, Pokemon Sun and Pokemon Moon.
Lunala is a Psychic-Ghost type, and it was introduced in the Generation 7 games, Pokemon Sun and Pokemon Moon. Lunala is a Legendary Pokemon, and the game mascot of Pokemon Moon.
Pyukumuku is a Water type, and it was introduced in the Generation 7 games, Pokemon Sun and Pokemon Moon.
Komala is a Normal type, and it was introduced in the Generation 7 games, Pokemon Sun and Pokemon Moon.
Passimian is a Fighting type, and it was introduced in the Generation 7 games, Pokemon Sun and Pokemon Moon.
Crabrawler is a Fighting type, and it was introduced in the Generation 7 games, Pokemon Sun and Pokemon Moon.