Retcon article(covers information that was retroactively changed)
Kermit T. Frog was a Human who was kin to descendants of Donald and Clare Raymond. He was directly related to Patrick Troughton and William Hartnell.
Frog's name was read out on a computer display of the Raymond family's genealogy, along with others such as Miss Piggy. (TNG: "The Neutral Zone", okudagram)
This character was only mentioned in writing.