Lytic polysaccharide monooxygenases (LPMOs) play a unique role in biomass saccharification as they catalyze oxidative cleavage of recalcitrant polysaccharides. Here, four new starch-active AA13 LPMOs were identified via phylogenetic analysis and functionally expressed in Pichia pastoris, followed by the investigation of oxidative activity towards different starch substrates. The four purified AA13 LPMOs were capable of oxidizing amylose, amylopectin and corn starch, generating soluble products. Among the four, FvAA13, which exhibited the best oxidative activity, was further studied. Its yield of oxidized products was 1.9-fold, 1.4-fold, and 1.3-fold higher than the previously reported NcAA13 when applied to starch substrates amylose, amylopectin, and corn starch, respectively. Furthermore, the oxidized product yield of FvAA13 was enhanced by 2-fold when supplemented with 100 μM H