For consumers, M-DISC media for DVD/Blu-ray might be about the best there is for long term storage.[1]

In the enterprise/experimental world there are things like Microsoft Project Silica[2][3] where they are storing data on quartz slides.

[1]https://en.wikipedia.org/wiki/M-DISC

[2]https://www.microsoft.com/en-us/research/project/project-sil...

[3]https://news.microsoft.com/innovation-stories/ignite-project...