Seems artists like drawing Pokemon OCs / player characters. I think similar to e.g. Avatar (FF14) it wouldn't hurt to make a Avatar (Pokemon) tag, especially for "named" characters.
I wouldn't be against this. Sometimes the player character can be customized to such an extent that they aren't recognisable as their canon appearance anymore. For example: post #4474508 is Gloria by the artist's intent.
That said, to what extent does a base design need to be customised before it stops being them and starts being an original character? For example: post #4256370 is still wearing some of Gloria's iconic garments such as her cable knit cardigan, traveller's backpack, and plaid green socks, but is otherwise unrecognisable. post #4397135 wears Gloria's default outfit in its entirety, but with a different hairstyle and eye colour. How would such cases be handled?