A couple of weeks ago, I featured an issue of issue of Master Comics wherein Captain Marvel teamed up with Bulletman. In thinking about that comic, I wondered what OTHER public domain heroes have teamed up. So I did a little digging around and found Prize Comics 24 which features the Prize heroes (Yank and Doodle, Green Lama, Doctor Frost and the Black Owl) vs Frankenstein.
The actual story is quite short and shows up late in the issue.
[ Prize Comics 24 ]
Thanks to a post from Boox99 over on the Golden Age Comics site, I also found out that Daredevil 1 which features many of the Lev Gleason heroes fighting Hitler.
[ Daredevil 01 ]
I find searching for such stories very difficult as most of my searches return World's Finest or JSA type of results. Anyone know of a nice list of such comics?