Some may be older. Ones I actually port to new machines and use are the perl "ren" script and the rdb relational database (perl) by Hobbs.
Source:
https://github.com/ironsmith58/RDB/tree/master
Article:
https://seann.herdejurgen.com/samag.com/html/v11/i01/a6.htm
Docs as pdf:
https://casegroup.rutgers.edu/lnotes/ccb550/spring20/RDB.pdf
For UI apps there’s not much I use that’s that old.
I bet most of the app installs these days are just kids tapping misleading ads they see in bad games.
Swiss army knife for file/SFTP/… operations on Windows