Useful depends upon if teachers backed up their courses, if you had automated backups going to 'filearea', etc.
If you can find files that are gzip in the sea of files in moodledata, they might be backups of courses.
find ./*/*/ > hashes.txt
hashes.txt file will be large and lines will look like:
Create a bash shell script called possibles in moodledata/filedir/
for i in `cat ./hashes.txt`
echo "Hash in que:" $i >> possibles.txt;
file -b $i |grep gzip >> possibles.txt;
That will create a possibles.txt file ... a large one - and you'll have to look through it to find what could be backups.
In possibles.txt you, hopefully, will see entries like this:
Hash in que: ./07/4f/074f9c58068de1f24902744625386c577c40663a
gzip compressed data, last modified: Tue Apr 4 06:40:11 2017
And even if you can't see a name, one could copy them out of
moodledata/filedir/X/X/X to a holding directory (/possibles/) by names
you created ... pbackup1.mbz.
cp ./07/4f/074f9c58068de1f24902744625386c577c40663a /possibles/pbackup1.mbz
Then using tar to view the contents of the .mbz files you've named (may not be backups) looking for moodle_backup.xml.
tar -tvf pbackup1.mbz |grep moodle_backup.xml
-rw-r--r-- 0/0 5558 2018-09-14 08:56 moodle_backup.xml
If last command shows there is a moodle_backup.xml then one could extract just that file to find the original name of the course.
Pain in the arse. Very time consuming. But, you have something ... which is better than nothing - IMHO.
'spirit of sharing', Ken