Lettercolumn contributor "T.M. Maple" was, as evident in the pseudonym, a Canadian.

https://en.wikipedia.org/wiki/T._M._Maple


Probably the most prolific letterhack in comics history. I myself mailed about 100 letters to publishers, 30 of which were published.

Others among the most prolific I would guess include Bob Rozakis, Guy H. Lillian, Jan and Dean Mullaney, Cat Yronwode, Mark Gruenwald, Ralph Macchio, Irene Vartanoff, and several others who escape my memory, most of whom later worked professionally in comics, or peripherally in comics fandom.