I've added my first contributions to DMs Guild. Feedback is of course welcome, but I decided to start simple. My next addition will likely be a map or an encounter.
I made these to make my life easier. The DM Screen of Superior Referencing has the vast majority of tables I ever have to reference, and even a bunch I know I'll need if my players ever throw me a curve-ball.
The Chronicle of Encounters Initiative Tracker has ways of tracking every condition I know of for my NPCs, including concentration. I use this, and it makes tracking things SO much easier.