If you go by your triumphs, in the "Lore" section, under "Marasenna," there should be triumphs for getting all the eggs in different sections of the Dreaming City. You should have one that will be incomplete, and will have a progress bar, that when you put your cursor over it, it will say "Destroy all Taken eggs in _______" (or something to that effect), and a X/X counter showing how many you've gotten in that area. Once you identify the area, it will help narrow down what you need to find.