Exactly, House of Secrets 92 and other first appearances from around that time period come to mind. It's a pitch black book, tough in grade... first appearance of an off brand anti hero, with a cult following for the cover artist. Yet, there are still double the copies of HOS 92 on census at 140. Last 9.2 did 7k recently but the one at Heritage (ending Sunday) seems poised to beat that.
Has always seemed to me that Vampirella, with Frazetta for the cover artist, #1 issue in the run, and first appearance of a staple bad girl like Vampi, is poised for much more growth than her competitors. Undervalued to be sure. Wish I would have kept all my duplicates.