As has been noted previously, 1953 was the year that saw the greatest number of individual titles and the largest number of issues published in the science fiction, fantasy and horror magazines, both “Pulp” and “Digest” formats (though Digest had largely replaced Pulp by this time).
The magazines published at least some time during 1953 were:
Weird Tales, Amazing Stories, Fantastic (Stories), Thrilling Wonder Stories, Startling Stories, Fantastic Story Magazine, Wonder Story Annual, Astounding Science Fiction, Future Combined with Science Fiction Stories, Science Fiction Stories, Famous Fantastic Mysteries, Planet Stories, Science Fiction Quarterly, Avon Science Fiction and Fantasy Reader, The Magazine of Fantasy and Science Fiction, Other Worlds, Universe Science Fiction, Galaxy Science Fiction, If Worlds of Science Fiction, Galaxy Science Fiction Novels, Two Complete Science Adventure Books, Space Science Fiction, Space Stories, Science Fiction Adventures, Dynamic Science Fiction, Fantasy Magazine/Fiction, Science Fiction Plus, Tops in Science Fiction, Rocket Stories, Vortex Science Fiction, Fantastic Universe, Beyond Fantasy Fiction, Orbit Science Fiction, Cosmos Fantasy and Science Fiction and Spaceway – 36 titles, 178 issues.
Of course, few of those titles lasted until the following year. By 1955, the total number of titles would be down to 19.