A good regional variant will always have to reflect the world it lives in! I totally agree! You have to cleverly combine either climate or culture of the region into a pokemon. And combined with a good design makes a very good regional variant! Say for example for a desert region...
So I've been working on regional variants for my own Pokemon, however, I've started getting curious about what other people would think make good regional variants! So let's share our own ideas and such on Regional Variants here!
For Example, These are some sprite edits of some I made...