Most flash drives have a storage capacity from 8 GB to 64 GB. Smaller and larger flash drives are also available but they're harder to find.
One of the first flash drives was just 8 MB in size. The largest one I've seen is a USB 3.0 flash drive with a 1 TB (1024 GB) capacity.
Flash drives can be written and rewritten to an almost unlimited number of times, similar to hard drives.
Flash drives have completely replaced floppy drives for portable storage and, considering how large and inexpensive flash drives have become, they've even nearly replaced CD, DVD, and BD disc for data storage purposes.