Agedu

Most Unix file systems, in their default mode, helpfully record when a
file was last accessed. So if you generated a large amount of data years
ago, forgot to clean it up, and have never used it since, then it ought
in principle to be possible to use those last-access time stamps to tell
the difference between that and a large amount of data you're still
using regularly.

agedu uses this information to tell you which files waste disk space when
you haven't used them since a long time.