Led, this certainly is an intriguing post. Never heard mention of another dedicated mold collector - you might be standing alone.
#1 is a masterpiece. Overdone? Maybe, but the hook eye & shank position pins suggest a seeker of perfection thru the medium of jig head creation. And the other mold design features - cupped micro sprue inlet gate, reverse triangle barb, minimal collar, close to head eye position, are the work of someone with an experienced working knowledge of jig heads. Many of us have ideas of how to improve stock mold designs, & this extraordinary craftsman expressed his to the limit of available tooling.
#3 & 4 are curious - like someone decided to combine Do-it cavity setup with Hilts inlet gating.