Memory storage. Pros & cons? [View all]

I need to free up space again on my devices, and am contemplating which physical format to use.

Cloud storage is not in the running, so these must be physical.

Options:
1) external hard drive -- SST vs OG

2) Cards (micro SD etc)

3) USB flash/thumb drive

While I like having everything in one place, I also favor decentralization. Also, most of the time no computer will be involved, so something easily portable for mobile devices.

Any prefs for cards over thumbs?

Aside from cloud or RAID, what is your archive method?

Also, suggestions for robust photo mgmt solution (again, not cloud)?

TIY