Dr. Toad did not originate from fanon, and the information on this page may not be entirely accurate to their canon. You may read more about this subject in the context of their canon on the following wiki(s):
Dr. Toad's attire consists of a white lab coat instead of his blue vest, with a white undershirt and a blue tie. He also wears khaki shorts with an orange belt, as well as a head mirror on his mushroom cap. He also carries around a brown briefcase with a strap he holds around his shoulder.
Dr. Mario World
Dr. Toad's first canon appearance is in the mobile title Dr. Mario World, where he is an unlockable playable character. His special ability has him select two random locations before clearing them of objects; his animation shows him summoning a stampede of Toads that run on stage before clearing out the chosen locations. A Virus claims that Dr. Toad accomplishes this via pollen, which Viruses are allergic to.