ZB (short for Zborowski-Bruchem after its inventors, Zbigniew Zborowski and Ron van Bruchem) is a very efficient but algorithm-intensive method which is a variation of advanced LBL methods such as the Fridrich method. After solving the F2L minus one corner-edge pair in whatever method the solver wishes, there are just two more steps: ZBLS (originally called ZBF2L), which finishes F2L while simultaneously orienting the edges of the last layer, and ZBLL, which finishes the last layer in one algorithm.
On his webpage, Zborowski claims that his method requires only 40 moves on average, which means that a master of this method should be able to get times that are significantly faster than those possible with Fridrich. Unfortunately, because this method has a total of 300 algorithms or 795 total cases, it would take a very long time to learn the entire method. Very few people have ever put full ZB into practice.