Many avid Pokémon players tend to have the same goal in mind of catching all of the different types of Pokémon in each game; however, players may be better off not catching them all. With 905 Pokémon currently in the National Pokédex, catching them all can be a serious challenge. Adding shiny Pokémon to that count doubles the number to 1,810 Pokémon, not including regional variants (such as Alolan and Hisuian forms). Regional variants make up 54 types (most Pokémon have one type of regional form; Meowth has two), plus shiny versions which brings the grand total to 1,918 Pokémon to catch to have a completely filled regular and shiny Pokédex.
However, as of November 18, 2022, Pokémon Scarlet and Violet will release, adding even more new Pokémon to the National Pokédex. So far only eight new Pokémon have been officially shown in the Scarlet and Violet trailer, but there is speculation that upwards of 80 new Pokémon may be added. Ultimately it isn't clear how many total Pokémon will be available in the game, but it's safe to say it will be a lot.
Related: How Pokémon's Future Games Can Reintroduce Regional Variants
Filling a Pokédex is no easy task and players shouldn't worry about catching them all, or at least not obsess about it. While a completed Pokédex is a point of pride for many players, filling it can be a tedious, time-consuming, and sometimes overly frustrating task. Unless players have the right resources, it can also be near impossible.
With almost 2,000 Pokémon in existence (and more than 300-500 of them available in any given title to catch if a player wants to fill their Pokédex for an individual game), playing Pokémon can turn into a job. Players have to grind through multiple Pokémon encounters and battles
Read more on screenrant.com