In addition to his BLACK MAGIC stories for Simon&Kirby Ditko worked on the CAPTAIN 3-D comic that S&K did for Harvey, and possibly other 3-D comics of the era (possibly unpublished), working with other artists on the backgrounds (as the process of creating 3-D comics was apparently quite labour-intensive)
I don't know how much Ditko there might be in that, but look for a newly coloured 2-D reprint in one of Joe Simon's reprints of the S&K material next year.
STRANGE FANTASY #9 [1953] had the story "Hair Yee-eeee", a story that Bruce Hamilton has identified as another (like "Stretching Things") that he sold to Stanmor and they re-sold to Farrell. Some people see a degree of Ditko in the art, though almost certainly not Ditko solo (there's a mark which might be an initial "SS" on the first page). This scene, for example:
Possibly related to the above, an artist named Sy Moskowitz briefly worked in comics around the same time as Ditko broke in, doing some work for Charlton, Gilberton (Classics Illustrated) and Marvel (including a few stories with Joe Kubert). I haven't looked at too much of it, but some people see a few signs of Ditko in a few of his stories, and Greg Theakston even included "The Mark of the Ripper" from Charlton's STRANGE SUSPENSE STORIES #21 [1954] in his book STEVE DITKO: EDGE OF GENIUS [2008]. I'm not 100% convinced it belonged, but judge for yourself.
No reasonable way of knowing at this point what role Ditko might have had in some of these stories, but speculation clearly labeled as such can be fun. Any other stories from that era you see something Ditkoesque in? Feel free to comment, and include a scan or two of a likely panel or two if you can.
Charlton's THIS MAGAZINE IS HAUNTED #17 [1954] featured the 7-page "3-D Disaster, Doom, Death" seen below. It's the story of Bruno Thor, a movie actor specializing in various monster types whose temper has gotten him in trouble and made him box office poison. Going out drinking after being thrown out of the studio, he meets a mysterious man who offers him a script called "The Devil's Pact", and... oh, you can pretty much figure out the rest from there.
"If Looks Could Kill" is a 6-page horror story from Charlton's THE THING #15 [1954]. A very strange little story about a doctor who gets kidnapped by a hypnotist who seems to have some enormous powers in his eyes, but can't think of anything better to do with them than penny-ante kidnap schemes. Then it gets really bizarre, with a lot of twists in the handful of pages. A pretty cool little story, and Ditko does a great job of picking out some key bits to give his special touch. Check out that close-up on page 3, for example.
"Dead Reckoning" is a 7-page Ditko story that appeared in Charlton's SPACE ADVENTURES #11 [1954]. Amusing little story taking common themes in crime fiction of the time and pretty much just translating them wholesale to a science fiction setting (with the conceit that one of the characters is a fan of 20th century detective stories). A lot of fun, as contrived as parts of it are.
Oh, this is a sweet bit of early Ditko from Charlton's STRANGE SUSPENSE STORIES #18 [1954]. The 6-page "Dead Right" features a reporter and photographer visiting the London home of a man named Mr. Mord, who creates grotesque wax heads of notorious killers. One head in particular horrifies the reporter, who has his photographer secretly snap a picture of it, which leads him to discover Mord's secret.
