This lists all 37 issues of Flash Gordon as being published by Gold Key. One look at the covers, though, tells another story. This is actually 4 different volumes.
1-11 is published by King
12-18 is published by Charlote
19-26 is published by Gold Key
27-37 is published by Harvey
I don't know if there's an easy way to bulk-edit and split them off into different volumes.