Emacs org-mode
I've been an emacs user since around 1979. My hands know where the keys are and which keys to hit to get things done. The fact that I don't need to lift my hands from the keyboard to grab the mouse to get something done (and causing me to lose my train of thought) is huge. This is something that the Apple OS does well and Microsoft doesn't seem to get. To make matters worse, lots of new tools are web based where getting data from one application to the next is near impossible without using the mouse and without interrupting my hands on my keyboard. So I'm thrilled that I now have a non-web based organizer that's in emacs (my favorite editor/environment), it's emacs org-mode. Now I can concentrate on the programming algorithms and not on my tools.
I've been looking for a text based organizer tool where I can put my work notes in some kind of format that I can dump into HTML or work with in an editor. I was looking at learning Microsoft's Onenote but I'll be honest, I really didn't like the idea of learning more because I'm already learning all sorts of new stuff for work (VMs, Docker, micro-services, etc, etc.). I only have so much bandwidth. Somewhere along the way I ran across Emacs org-mode. I decided to give it a try and was overwhelmed with all the options and didn't really come to grips on how to get started. Every once in a while I'd try again and make no progress. Then I found a Uncle Dave's Emacs Videos (start with Org-mode Tutorial 1 - Introduction and basics). While I'm not too thrilled about the profile picture (Pepe the frog, now an alt-right icon) I am thrilled with the material, just emacs. One word of warning, turn up the volume otherwise you won't hear Dave. Anyways, he explains things in a way that is useful to learn enough about org-mode to make it useful in day to day usage (business and hobbist/DIY'r). So with just the first 4 of 5 tutorials I've learned something I can use in my day to day notes needs. I'd also recommend the Emacs Tutorial 6 (Introducing: org-mode). I'm certain there's a lot more to learn and options I'll never need or use but so far I'm thrilled I have a tool that works in both Linux and Windows. And I'm looking forward to a tool that can export my notes into HTML so I can throw them up on the 'net. I'm finding that it's a lot easier to search my notes with Google and I don't have to drag my computer with me.