Non-metal substances such as iodine, eosin, tetrabutyl iodide, and 2,4,5,6-tetra(9H-carbazol-9yl)isophthalonitrile, which are radical initiators in homogeneous catalysis, possess high frequency of co-occurrence with regioselective synthesis, diastereoselective synthesis, and cross-coupling reactions (Figure ). Metal substances like cobalt, iron, nickel, and copper mainly co-occurred with cross-coupling reactions, oxidation, reduction, hydrogenation, and electrochemical reactions. Figure lists the most reported uses in the homogeneous catalysis dataset. In addition to the general use cases such photocatalysts and organocatalysts, cyclization, cross-coupling, and oxidation catalysts are among the most reported uses. Polymerization, ring-opening, hydrosilylation, and oxidation in particular have a high patent to journal ration indicating commercial interest.