Hand saws can be used in conjuction with bolts, clamps and files to cut threaded rods. However, the rod can move around and the threads can become squashed if not secured properly.Various power saws can also be used, but these may produce sparks and a cut that requires deburring.
Grinders can be used on threaded rods, but they will definitely produce sparks and a fire permit may be needed. Again the rod should be secured using bolts and vices.
Powered rod cutters
There are powered versions of the tool available. These work in a very similar way to the hand tool. They are capable of cutting stainless steel.
Rod cutter ratchet
This tool is similar to a threaded rod cutter, but is for cutting already installed threaded rods. It has a ratchet and two handles so it can be used overhead.