Hi Ben – I’ve recently found the following site and multitrack library run by Mike Senior (Cambridge Music Technology: https://www.cambridge-mt.com/index.html (click on “Mixing Secrets Free Multitrack Download Library”).
The library has lots of multitrack recordings for download and practice purposes. You will have to do a bit of conversion and renaming of files, but not a big deal.
Hope this helps.
Best,
Armin
