Pokemon Arts and Facts - Find us on BlueSkyさんのイラストまとめ

According Atsuko Nishida and Ken Sugimori the 3 Kanto starters were designed after their fully evolved forms (Venusaur came before Bulbasaur). They are based on Frogs, Lizards and Turtles. The Pokemon were designed as sprite art first then converted to color drawings by Sugimori.

Red and Leaf/Green's battle poses in Let's Go, Pikachu & Eevee! resemble their battle poses in FireRed & LeafGreen.

Rosa also owns a Serperior in Pokemon Masters. This is following a trend where she had as Serperior in the Pokemon Black 2 and White 2 Animated Trailer, as well as a Snivy in the Kotobukiya ArtFX J figurine.

Official artwork of Slowking devolving back into Slowpoke after loosing the Shellder on it's head. This art was used for the Yadon Paradise section of the Japanese Pokemon website.

Official concept art of Darkrai.

The lower left image was drawn by Ken Sugimori made in 2007 for Pokemon Diamond and Pearl, it was likely made to promote the Darkrai events being released, and the movie, The Rise of Darkrai coming to theaters.

Also they gave Darkrai a butt

Mega Ampharos' design is likely a visual pun as it is an Electric/Dragon Type. Ampharos' Japanese name is デンリュウ (Denyru), coming from electric current 電流 (denryū), but it also translates to Electric Dragon 電竜 (den ryū). The pun is lost in most other languages.

This is Hitoshi Ariga! You may recognize his work for the Mega Man franchise. He has done many art for the Pokemon franchise such as art for the TCG, figurines and he even designed some Pokemon!
-Zeraora promo art
-Black and White TCG concept art
-Kotobukiya art of Red & Pikachu

Art of Pikachu created for the 30th Anniversary of Game Freak

Outside of Super Smash Bros. Brawl's Chronicle list and anime references. Detective Pikachu is one of two spin-offs mentioned in Smash games, being a Spirit Battle in Ultimate using Pikachu's 6th color. The other is the ZERO-ONE trophy from Pokemon Snap in Melee #DetectivePikachu

According to the Pokedex, Corphish and Yungoos are not from Hoenn and Alola with their population growing after being imported. These are common traits of real world invasive species.