Some models are designed for phones and cameras. They are concealed and can’t use USB ports. They are slower.

— For laptops, you can consider all types, if you have the required ports

Fastest .. USB-C and some USB-A devices, up to 400MB for reading. Standard SSD offers 500MB.

SD cards (concealed) .. require card readers. Speed is up to 200MB for reading, unaffected by SD card adapters.

SD cards can be a suitable choice if you want to keep your ext storage permanently attached. However, SSD offers better reliability and longevity for day-to-day storage in computers compared to SD cards.

Warning: installing software in these ext storage devices … may fail, although portable USB-installers should work.

— Device cost … depends on read/write speed, stick-out and GB. For 64GB (becoming smallest), typically $10+, very affordable.

Price tends to drop over the decades, as smaller, slower models phase out.