I use a system of "a bit of everything." I have wordpads/notepads on my pc desktop for all sorts of things. (I counted 8 by the way.) 4 of them on the left monitor have to do with Etsy post descriptions that I didn't want to lose and needed to remind myself to actively work on them. The products have been on Etsy for over 2 years now, but I still can't accept a deletion of them just yet.
On my right monitor, I have one for jot notes, for a cyberpunk "short story" I was working on back in... checks properties info... September of 2022. I have other info and related inspiration on my Google Drive and even a dozen images collectively from ArtStaion, and Pinterest. And now that I think about it... I have several images saved to my hard drive somewhere. (Oh gawd. I just remembered that I have a collection of them saved to my alternative Imgur account, "So I won't lose them.")
I don't have ADHD, do I? /s
Next I have Lines and Phrases. This is where I save anything that I feel could be used in an aspect for my story telling. Here are a few entries to give you an example of what I'm collecting.
'A vast tapestry of wonder.' - No Man's Sky
From: The Pigeon Tunnel (documentary) "Betrayal fascinates me. I've lived through a period of endless betrayal." "In many of the stories, there are dupes and string pullers. Those in control and those controlled by others."
"That's the strongest argument I've ever seen for the existence of destiny."
Star Trek: Discovery S1 E10 (Captin Isaacs)
The next two wordpads have info that I often need to copy paste and a few things I look at as a reminder from time to time.