Form "Zero", while not an actual form of lightsaber combat per se but rather an ethical principle, was the idea that Jedi should know when to use their lightsaber and when to find an alternative means of solving a problem. This millennium principle is mentioned by Jedi battlemasterSkarch Vaunk in The Jedi Path: A Manual for Students of the Force and was supported by Jedi MasterYoda to address the need of the Jedi to restrain themselves when tempted to use "aggressive negotiations," and instead use another well-developed Jedi skill, such as the Jedi mind trick. This was a form used to arrive at a solution without resorting to violence; one that was favored by Felanil Baaks.
Yoda used to quote of the Thythonese Sky Judge Culoph who said:
In the days of the New Jedi Order, Jedi Master Kyle Katarn would teach his students, among whom were Jaden Korr and Rosh Penin, that often the sight of an unignited lightsaber would be enough to cause individuals that might be potential enemies to become more cooperative. Katarn had applied this principle himself years earlier to extract information from an uncooperative bartender in Reelo Baruk's cantina on Nar Shaddaa.
Fay was also famous for never raising a lightsaber. She used the Force to bring harmony rather than fighting, and if needed, fought using only the Force. In fact, it is unknown whether she actually carried a lightsaber.