Chemical structures of the main types of secondary metabolites (SMs) produced by filamentous fungi ^[1], based on the enzymatic activity of: (a) nonribosomal peptide synthetase (NRPS); (b) polyketide synthase (PKS); (c) terpene cyclase (TPC) for terpenoid production; (d) a number of enzymes for alkaloid production; (e) NRPS and PKS for production of NRPS/PKS hybrid; (f) NRPS and TPC for production of NRPS/terpenoid; (g) PKS and TPC for production of PKS/terpenoid; (h) enzymes for alkaloid production and TPC for production of alkaloid/terpenoid; (i) other enzymes for production meroterpenoid with unique structures (MUS), or NRPS-independent siderophore (NIS), or other types of molecules.