I’m specifically referring to microSD cards here, but I’m too lazy to type that every time and I doubt many people will think of full-sized ones anyway.
I got two 256GB SD cards (Samsung pro plus something) for Christmas, but I can’t think of a good use for the second one.
I have a Raspberry Pi, currently with a 32 GB SD card, where I’m gonna put the first one.
My phone has 128 GB of storage, which is already enough for me.
I’m considering putting it in my Nintendo Switch, but it already has a 64GB SD card, which is enough for the 2 non-physical games we have.
I plan on getting a Steam Deck once I can afford it, but that already has a lot of storage.
I don’t have a camera or drone or similar.
Selling is not an option.
A refund is technically an option, but I’d rather find a use for it.
Retro gaming is fun. If you don’t mind pirating games, you can put all of the N64 games, SNES, Gameboy, lots of MS-DOS classics, C64, Playstation 1/2 games, Arcade games etc on it and play some Frogger or Banjo-Kazooie. That’ll fill 256GB. Emulators are available on many platforms. Raspberry Pi, Android, PC, …
You can also stick it into the SD-Card slot of your laptop and use it as additional storage.
If your devices are a bit older: There are adapters to use micro-SD cards in devices that only accept full-size cards. They come for free with some micro-SD cards or should cost a few cents.
archive.org has some old games. Some of them are legal to download or abandonware and somewhat a grey area. Illegal sources for 256GB torrents of old games would be something like www.arcadepunks.com or maybe rompacks.com but I wouldn’t recommend pirating games from your own internet connection especially not with bittorrent.