I am new to the world of Linux and as part of my learning I would like to understand if it is possible for non-root users to have the ability to run their own backup applications apart from an over-arching backup of the server. If it is possible, what applications (GUI and command line) exist that will allow non-root users to backup their data?
Sure - why wouldn't they be able to? Of course it goes without saying that they'd only be able to back up files that they have at least read access to, and that they'll need write access to wherever they're storing the backup files.
I'm not sure about GUI tools, but
tar -czf file.tar.gz /path/to/files
via cron is usually what I see being done, or possibly using rsnapshot or one of its variants.