pokemon

The oeverexposure is a big factor yes (Pikachu and Charizard are pretty much the official whores of the franchise). Gets more variants than Charizard, and gets variants solely so that it can be shoehorned in context where there's no need for it, such as flying battles. Doesn't help that originally Pikachu was more rotund but in the later seasons of the anime and since around G5 in the games they gave it anime hero body proportions, which also sucks.

Haven't written any Pikachu in my works so far because why would I, I hate it. But if I ever need to have some bit NPC be outright demolished and mauled in a fight, Pikachu is among the top candidates.