The Genwunner

Anything beyond the original 151 Pokémon isn't a Pokémon!

The person who believes the first of something (like the first season of a TV show or first installment of a video game series) is the only one that actually matters in comparison to the later works. They may see this as true as they believe the sequels or later seasons do what the original did wrong, making them inferior to what the franchise in its earlier times was.

The Genwunner got their name from genwunners in the Pokémon fanbase who believe the only real Pokémon games were Pokémon Red, Blue, Green, and Yellow while everything proceeding is a spit-in-the-face to the initial image of Pokémon.

A person can only be a Genwunner if they think that the single first of something is good, not the first few.