And straight from the "B" league of supermen-wannabees are Steel Sterling and Doc Samson. Two scientists who jury-rigged their equipment to gain superhuman strength and durability, in part thanks to radiation the ultimately comes from the sun.
While Samson was always a supporting character for his more powerful contemporary and inspiration, the Hulk, Sterling was a man-unto-himself never depending on others' fame to elevate his own status. As such, Steel is much more prominent in his universe than is Doc in his. However, were these two men to ever meet, they undoubtedly would get along swimmingly after initial fisticuffs had already ensued.