I dunno, but its a good idea! if your into non-original songs, you could just improvise over a track someone else made and make/mix it in a total of 10 minutes instead of the hours you might need for your own song. Theres some here that exclusively improvise over others works; they might be able to help out? :wave:
There are sites out there, I don't have a direct link but you can do a google search for "free backing tracks" or whatever and find them.
I found ones for Iron Maiden and Metallica without much effort.
The best backing tracks I've found come from LickLibrary. You have to pay for a subscription, but the resources are awesome. Stevie Bees turned me onto that site.
the main thing i wanted was just something to improvise over, not necessarily other artists songs, but I'll definitely take the resources. greatly appreciated