This would have been useful for me a few years ago! My childhood Wii U had an eMMC failure and I ended up selling it to someone who soldered a new one in while I bought a standalone console off the internet.
A few months ago I picked up a copy of Pokémon Sapphire at a game store in Quakertown, Pennsylvania and the previous owner's save file was left on it. If you are Heather, here's your save!