I'll start off with the item which inspired this post, the egg separator that my wife, /u/accessaces, prefers and recommends: https://www.amazon.com/Internets-Best-Separator-Breakfast-Strainer/dp/B01LZ5NHDA

It is nice and cheap but is reliable and easy to use. It works better with fresh eggs and you should always separate eggs one at a time into a small bowl and then transfer the whites to the larger bowl to avoid any chance of yolk contamination, or worse, a bad egg spoiling the whole batch.