In the Star Wars Universe, lightsabers are a sacred tool to the Jedi and Sith alike. Luke Skywalker's weapon even lived on into the new trilogy as the chief weapon of justice and liberation the heroes and members of the Jedi Order wield. However, Luke wasn't the only Jedi with a lightsaber, and he wasn't the only one who lost his either. Despite his skills, Master Yoda lost one of his lightsabers as well.
Yoda worked with Professor Huyang, as many Jedi did for centuries, to build his weapon. Under the tutelage of the droid, Yoda got his kyber crystal from the icy caverns of Ilum, understanding how these minerals were living, breathing things. They felt pain and were connected to the Force, making them a true extension of both the Light and the Dark.
In time, Yoda would use it to try to protect the galaxy on the council, taking his green blade into the Clone Wars, against Separatists as well as his former apprentice Count Dooku. He could stop and deflect Sith lightning with it too, making it clear he held more power and talent than the average Sith.
Sadly, he lost his lightsaber in Revenge of the Sith when he battled Darth Sidious. He and Mace Windu had figured out the politician's true intentions and after Palpatine killed Mac. Subsequently, Yoda confronted the boss in the Senate Building. It led to a brawl as Yoda kept jumping around, trying to slice Sidious up as the would-be Emperor unleashed bolts of energy to disarm him. Sadly, in the fracas, the Jedi Master fell to the Senate floor from hundreds of feet up as the gravitating chambers were thrown at him, dropping his weapon along the way.
After that brutal loss, Yoda had to flee, realizing this era of the Jedi had indeed come to an unceremonious end. As for the weapon's fate, we'd discover the truth in 2017's Darth Vader #1, by Charles Soues, Giuseppe Camuncoli, Cam Smith and David Curiel. Grand Vizier Mas Amedda held a public meeting on Coruscant, denigrating the Jedi as oppressors and villains to the gathered citizens. He spoke of freedom and that after Order 66, they needed to burn the lightsabers collected to celebrate. Among the weapons of the fallen Jedi was Yoda's, and as they burned, their kyber crystals caused a large explosion of energy as if it were a beacon of the darkness to come.
Palpatine used this as a lesson, teaching Vader that rather than gift him Yoda's weapon, he needed to take one for himself. Slaughtering Jedi, then bleeding crystals made their blades red so this was the path he needed to follow in his training, to show the Emperor he truly belonged at his side.
In Yoda's latter years, Yoda had another blade that was like one of many that he built over the years. However, it's still sad to have seen how the famous weapon met its demise as was the chief weapon of one of Star Wars' most iconic characters during a pivotal era of the franchise.