If you are talking about offsetting the off balance condition caused by parts that are not symmetrical or are mounted off center, so that your lathe is not jumping up and down, yes, that can be done. It is easiest to do if the work is mounted to a face plate, because there are slots for mounting counterweights. You can test the balance by taking the lathe out of gear so the spindle turns freely. The heavy side will of course be pointing down and the counterweight needs to be mounted at the top. When the spindle does not turn by itself when you let go of it, regardless of clock position, you are probably close enough. Test the results at low RPM, gradually increasing the speed. With standard chucks, it is tough to mount a counterbalance. Sometimes a balancing feature can be added to the part, either bolted on or sacrificial after completing the turning.
WARNING: Be careful, and try not to lash up something stupid. A lot of centrifugal force is created by spinning stuff, and you REALLY do not want anything flying off.
I am not aware of any commercial attachment for easily achieving a balanced condition. There are an infinite number of possible things that might be mounted to the lathe, and no attachment would work for all of them. You will need to be creative...