If you want Steve Ditko comics then you are in the right place. Golden Age has plenty of Ditko in horror, sci fi, and superhero genres (and maybe some others that I missed as well). Most of the issues we have are from his Charlton days, but there are other publishers as well. Probably his most famous GAC series is Captain Atom
Captain Atom started in Charleton's Space Adventures (issues 33 - 40). Later it was reprinted in Strange Suspense Stories (issues 75 - 77) and then Charleston changed the title to Captain Atom with issue #78 and included new stories. In the Charlton Comics run, Captain Atom was a scientist named Allen Adam and gained his abilities by accident when he was seemingly "atomized" and then somehow reformed his body, now existing as an atomic-powered being.
Another interesting series with Steve Ditko art is Blue Beetle. In the mid-1950s, Fox comics went out of business and sold rights of the blue beetle to Charlton comics. I believe Ditko did the first 5 issues of this 1967 Charlton series.
If you are in the mood for some giant monsters (alla Godzilla) then check out this Gorgo series which has Ditko in many of the issues from 1 - 16 and the Konga series which has some ditko in some issues up to 15. For a touch of mystery and sci-fi do check out Mysteries of Unexplored Worlds which has lots of great Ditko up to issue 14 or so. You also won't want to miss Out of this World with Ditko up to about issue 16. For some pure Sci-Fi Ditko then look no further than Outer Space. This 1958 Charlton series has Ditko in issues 18 - 21.