There are some expensive techniques involving trawling the symbol table, then every pad in every format and code reference which might be able to locate all the names by which a certain variable is referenced. If that failed then it might also be possible to write some C code to trawl through perl's arenas.

The thing is, this is going to take a bunch of runtime because each lookup has to check a few thousand locations (if you're lucky). You'll be better off thinking of a different solution. Perhaps like SQLite or DBD::CSV.