We know as a fact that a lightsaber can be stopped during a fight by another lightsaber. Also I remember two more Imperial weapons that were able to stop a lightsaber:
Do we know of any other similar weapons that can fight against a lightsaber?
Any weapon crafted using a Cortosis-weave could withstand a lightsaber wielding opponent.
There are references in Knights of the Old Republic game to the cortosis-weave technique in the making of weapons. I don't believe there is any specific movie canon reference to anti-lightsaber technology
In addition to @Rogue Jedi's fantastic answer, the race of Sith also produced weapons capable of deflecting lightsabers.
I’m going to list specific weapons by their effectiveness against a lightsaber in combat:
The Laser Scalpel. It most likely utilizes similar plasma tech to that of a lightsaber, but you’d be screwed fighting with one in most cases.
The Laser Knife. It’s basically a lightsaber in the shape of a small knife. Unlike the laser scalpel, most people used it in combat, and it behaved quite like a lightsaber would.
Stun batons/electro-batons: Most stun batons probably wouldn’t be able to penetrate the armor of a storm trooper, but some can do some real damage/block lightsabers.
Neuronic whips. Torture devices in the form of electric whips. Unpredictable, but it might work against an unskilled lightsaber wielder.
The Blastsword. It’s a blaster you have to hit someone with, but I doubt you could actually properly defend yourself against a Jedi with.
Electroswords. This one really depends on what they’re made of. Some can actually block lightsabers, but others cannot.
Power lances. I doubt these could really block a lightsaber, but they’re so ridiculously huge that if you were to charge at a lightsaber wielder with one on a speederbike, it could pose a serious challenge for them.
Energy lances. These can shoot out energy beams so I think that might distract a lightsaber-wielding foe long enough for a good blow.
Felucian Skullblades. These can actually consistently defend against a lightsaber, so its probably a good idea to have this one as your first pick above the ones listed previously.
Electrowhips/shock whips. These things are really only used for torture, but they can consistently block lightsaber attacks. The downside is that using these weapons is quite hard, and they can also be unpredictable. But that might work to your advantage against a lightsaber-wielder.
Electrostaffs. Walmart grade lightsabers, but they can definitely block lightsabers and make life difficult for whoever is faced against them. So long as they’re made of Phrik, that is.
Force pikes. A better version of the energy and power lances; these things can consistently block lightsabers and are very effective against them.
Praetorian guard weapons: Unless you’re in a Star Wars sequel trilogy movie, you actually have a decent chance of defeating a lightsaber with one.
Force imbued blades/any Sith or Jedi artifact: Some of these are arguably BETTER than a lightsaber!
Lightfoils: Lightsabers for non-force wielders. Enough said.
Amphistaff: Living creatures that eat lightsabers for lunch.
