Big congrats again! A huge achievement to complete an all-language species collection! I love reading about each species collector’s achievements and struggles with all languages. Some of the most unassuming cards can turn out to be some of the hardest to track down. All languages is really a beast, and I very much appreciated how you broke down each set and described what cards were available for that art and in what language. It was all very informative.
I’ve helped tracked down a couple unlimited XY10 and XY8 cards for other species collectors, and from what I remember, like with you, it’s always the unassuming bulk listing of random cards rather than single listings that eventually led to success. Also digging through all listings after searching just the pokemon name, without any additional details, like @eeveeteam always advocates. It’s great to read about the lengths to which you went to try and pry one out and then you just finding it for super cheap one random day—perhaps a small reward for your perseverance and dedication! And, as is customary following these year-long chases after unassuming cards, two more unlimited XY8 Staraptors will surely appear on the marketplaces in the near future in short succession 
Congrats again, and thanks for the beautiful post!