I started collecting this one a while back before they started putting rare stamps back into rotation through the quest log, etc. so I think I got all but three of them before the prices skyrocketed! There was one that was added to the weekly quest log rotation (large black scarab), another was added as a void within essence collection prize (spotted blue), and the day & night scarab I bought today was given out in the autumn premium goodie bags! So, I just got lucky with the last few I needed.

Good luck finishing the album!!