Positive Man is the name of several unrelated characters in the DC Universe. The most well-known is Larry Trainor, formerly Negative Man, a member of the Doom Patrol. Having evolved beyond his original state, he can expel positive energy from his body, effectively altering reality by doing so. An adversary of Supergirl also went by the name "Positive Man".
Larry Trainor was created by Arnold Drake, Bob Haney, and Bruno Premiani, first appearing in My Greatest Adventure #80 (1963), while his Positive Man identity was created by Gerard Way and James Harvey, first appearing in Doom Patrol: Weight of the Worlds #2. (2019) The Supergirl villain Positive Man was created by Jerry Siegel and Jim Mooney, and first appeared in Action Comics #287. (1962)


