various sample-packs ... free
found lots of samples (oneshoots/drones/loops) over here at "99sounds.org"
Sound Design Tools
Weird Side (Tech)
Since many of the samples do have long filenames, I'm using a tool called "Bulk Rename Utility" which is capable of very powerfull batch-renaming.
But be carefull. Powerfull tool that does not ask questions. If you screw up you get what you ask for.
(hint: use F5 to refresh screen; and always press CTRL+A to get the preview of the renaming; use Selections(12) to preselect files "*"=all; use Repl.(3) to replace, use Remove(5) to shorten, use Move(6) to move the numbers a the end of filenames to front)
Use a backup-directory with your samples to rename since you will screw up a rename step for sure at some time.