Jorge Linares has fought for 8 vacant titles. He won 7 of them only losing the Vacant WBC Light to Demarco by KO. The only title he earned which wasn't vacant was the WBA Light he got off Crolla. That was a fight in which he also fought for the Vacant WBC Diamond Light which was an upgrade.
GGG fought and won the vacant IBF recently and won the vacant WBA and vacant WBC without even having to put up a fight. Leo Santa Cruz has fought for 3 vacant in 3 different weight classes.