Honestly, there really aren’t any. Even if hard drives are expensive, they still represent your best choice for local storage alongside cold web storage.
Blu-ray media is still being made by Verbatim and Ritek, but it has never been a suitable long-term storage option due to both cost and the fact that it is subject to disc rot. Even a lot of the so called “1,000 year” M-disc media sold today aren’t actually true M-disc media since Millenniata went bankrupt (tests have shown that Verbatim changed the formula and is just selling high-grade standard Blu-ray discs as M-discs). And, on top of that, Blu-ray/M-disc drives are becoming more scarce and expensive.