Other than the gold standard what non fiat currency is a good investment?

It sounds like you are asking what good barter items might be. It would have to be something that lasts a long time or something that can be created continuously, something physical, and something that everyone needs. I’ve heard ammunition before, but ammunition isn’t universal. Not everyone has the same caliber. So stockpiling every sort of caliber, or even the most popular calibers isn’t practical.

Something that lasts or can be regenerated, is physical, and everyone needs or wants….hmmm…I’m thinking something in the sativa family. If things get to the point where the barter system is kicking in, growing your own and trading it for things you need is a win-win.

GPUs.

None.