Work notes I have separated by subject across various text files, using ### to delineate a topic. I then use Sublime Text 3 find in all open files (has regex option) as my notes can overlap the way they're separated.

Google Keep is what I use when I need to make a fast note to look up something later with no urgency.

I'll use PushBullet to push a link or something from my phone to my desktop for when I'm back at that device (I have it setup on my phone/laptop/chromebook).

For focused writing, I'll use a vim plugin called Goyo (https://github.com/junegunn/goyo.vim).

I think I'm a bit of a mess but this is actually a refinement of systems. One day it'll be perfect!