According to Porygon's Pokemon Red and Blue Pokedex, "A Pokemon that consists entirely of programming code.

Source: https://gamerant.com/pokemon-original-150-rarest-pokemon/

A trade is considered special if it includes a Pokemon or Pokemon Form that's not already in the players' Pokedex, a Legendary Pokemon, a Shiny Pokemon, or an Ultra Beast.

Source: https://gamerant.com/pokemon-go-how-to-catch-mr-mime/

Fans anxiously await the release of each generation to see what Game Freak has cooked up to add to the ever-expanding Pokedex.

Source: https://gamerant.com/best-designed-pokemon/

In fact, its Pokedex entry in reads "Mega Evolution also affects its brain, leaving no other function except its destructive instinct to burn everything to cinders."

Source: https://gamerant.com/biggest-pokemon-ranked-size/

Magneton appears as a Paradox-type in Pokemon Scarlet and Violet, and despite being less powerful than Terastal versions, it is considered essential for Pokedex completionists.

Source: https://gamerant.com/pokemon-fan-build-magneton-security-cameras-magnets/

Rather than battling, players compete to see who has the highest or lowest HP, Weight, Pokedex Number, Height, or Card Number.

Source: https://comicbook.com/gaming/news/pokemon-scarlet-violet-tcg-happy-meal-mcdonalds/

Something about Mewtwo clashing with Darkrai causes a unique side effect, and the last few panels of this volume show all three Pokedex Holders now frozen in stone (as well as Silver).

Source: https://gamerant.com/pokemon-manga-disturbing-moments/

True Pokedex completionists have acquired all of these hard-to-get Pokemon.

Source: https://gamerant.com/pokemon-original-150-rarest-pokemon/

While there are a number of Pokemon programmed into the games that are not available to be captured and are not part of the Paldean Pokedex, there is no indication that Gloom, Cottonee, or Helioptile are coming to the games.

Source: https://gamerant.com/pokemon-scarlet-violet-get-sun-stones-guide/

With the release of The Teal Mask DLC, players are challenged to fill in their Kitakami Pokedex as they explore the region.

Source: https://gamerant.com/pokemon-scarlet-violet-how-evolve-cutiefly-into-ribombee/