Main Series Pokémon Games

The Main Series is a term often utilised by people to differentiate the core traditional Pokémon games with the various Spin-Off and App titles that were given. While many believe it a fan term, it has a root in official terms with the "Pocket Monsters Series" (『ポケットモンスター』シリーズ) being the official Japanese term for these games

These games are traditionally, albeit not exclusively, developed by GAME FREAK and help drive the Pokémon franchise forwards. They can also sometimes connect with various Spin-Off titles to get bonuses or even receive Pokémon into the Main Series titles

In recent years, there have been twists in the Main Series games that branch it out to different subseries. These are still officially counted as main series titles, but offer slight twists on the gameplay.

The Traditional Main Series games are where it all began and continue to be the driving force of the franchise. These games feature you as a Pokémon trainer going through a region, stopping antagonistic teams and battling with your Pokémon.

Within the Traditional Main Series there are a few subsets:
There are the games that start the generation. These come every 3 to 4 years
There are Enhanced/Upper/"Third" Versions. These games take the start of the generation and expand on it with an altered story and various gameplay improvements. Sequels also fall into this category
There are remakes. These games are older generation starting games but brought up to the standards of the generation of release including mechanics and features that have become standard.

The Let's Go games were introduced in 2018 as a new more casual orientated offshoot of the Pokémon Main Series. This follows the same traditional style of gameplay but pulls back on a lot of mechanics including the battle system in order to make it accessible.

The Let's Go games were designed as an amalgam of the traditional main series games and the gameplay of the Pokémon GO spin-off game.

The Legends games were another twist on the main series gameplay. The first game of this was set in times before the traditional series when the region was just starting out, before Pokémon Trainers and Pokémon Leagues were a thing. It features seemless gameplay between the overworld and battles, but is listed as being an Action RPG, rather than the traditional RPG genre of the other Main Series titles

Unlike its other Main Series games, this set of games is Single Player only.