A chuck from a defunct cordless drill, preferably keyless, works great for holding all sorts of small round tools and brushes commonly used in case prep and reloading. You can get a better grip on a chuck than on some small diameter tool handle.
A 1/2" chuck will hold a case deburring tool.
Junker drills can usually be found at garage sales or thrift stores cheap. Getting the chuck off can sometimes be a challenge.