Over the past two years, there have been many reveals of leaked beta Pokémon that were either scrapped or redesign, so this was won’t seem as farfetched (or Farfetch’d, if you will). It’s best to take all of these leaks with hefty grains of salt, but a recent 4Chan post revealed many sprite variances from the Nintendo DS’s Pokémon Diamond and Pearl entries:
As pointed out by Lava Cut Content, the Charizard is the most notable with the female variation only having a single horn on their head rather than the original two. This is also interesting as this design matches early artwork from 1997 where Charizard was indeed depicted with just one horn.
As stated before, take all of this with grains of salt but if true, this makes for another interesting snippet into the history of Pokémon.