Gold Key used 4-5 page "filler" series in their Silver Age comics...
...some of which proved popular enough to receive their own titles!
Based on concepts used in Murray Leinster's Hugo Award-winning story "First Contact" which premiered in Astounding Science Fiction May, 1945, this Russ Manning-written and illustrated series debuted with this tale in the back of Gold Key's Magnus: Robot Fighter #1 (1963), which Manning also scripted and drew.
The series continued until #29 (1971), when Gold Key increased the amount of advertising pages, eliminating the need for the shot backup stories in their books.
Gold Key tried the strip in it's own title with two one-shots reprinting some of the stories, but neither sold well.
When Valiant/Acclaim acquired rights to most of the Gold Key characters in the 1990s, they did a two-issue reprint of the first 14 stories in the hope of leading into doing new material based on the strip, but again, the books didn't sell.
We'll be re-presenting not only the already reprinted material, but the entire second half of the strip's run which hasn't seen the light of day since the Silver Age!
Watch for it!