Smogon University - Pokemon Showdown! has been updated with new HD sprites. Please have a look->

Pokemon 100 Voltorb Pokedex: Evolution, Moves, Location, Stats

Help with Pokémon Showdown? - PokéBase Pokémon Answers

Rejected - Changing Sprites on Showdown

Legality Changes by Yellow and Japanese Blue [QC 1/1] [GP 2/2] [HTML-ready!]

CAP 25 - Part 11 - CAP 25w Sprite Submissions

Horo's Trainer Sprite Gallery [COMMISSIONS OPEN]

Smogon April Fools' Day Sprites and Miscellaneous by Quanyails on DeviantArt

An Introduction to Spriting - Smogon University

An Introduction to Spriting - Smogon University

Brumi-Workshop (still in break, sprites commissions closed)