Happens a lot.......As I have posted in the past, I will see something I've done myself and thought I "invented" it, only to find that someone else has "invented" it.

One example: Catskill style flies were the flies I was most familiar with growing up in fly fishing. They were the most popular dry fly patterns.
Sometimes, I found that wrapping the hackle of those days (often with thick and unruly stems) on a very TINY amount of dubbing as sort of a "pillow" for the hackle allowed the hackle to wrap better. I mentioned it to the owner of my local fly shop.
A year or so later, I saw on a package of hackle - not sure if it was Whiting, Metz, or Hebert - it showed doing this very thing!!!!