Lightsabers are cool, regardless of your opinion of the movies, lightsabers are really cool. From the fact that it can retract the blade to the lack of effort needed to cut through anything only makes them seem even better and I feel I speak for many science fiction writers when I say I wish I could use them, but unfortunately unless you are writing a fanfiction, you are out of luck.
Many series that really want to use lightsaber-esque weaponry tend to use a weapon similar to them like Halo's energy sword or Bleach's laser swords. I am asking if there are any other options. I am not looking for the down and dirty, hard core science details of such a weapon, rather the simple and basic. What weapons (real or fictional) would be able to match the lightsaber in its usefulness and functionality?