There are so many add-ons for Blender, I needed to keep track of those I find the most helpful. Hopefully it’ll save you some time.
QuickSnap
This is a great free and open-source add-on helpful when you want to align vertices, edges, faces or objects to anything else in your scene.
https://github.com/JulienHeijmans/quicksnap
Multi-Camera Toolbox
I developed this free and open-source add-on to have an easy way to allow for the cameras in the scene to have different render resolutions. It makes managing your cameras very easy. You can even jump between them with the keyboard (if you enable Highlight selects Camera).
https://github.com/Gatada/MultiResolutionCameras
BlenderKit
This add-on gives you access to all the BlenderKit assets available. You will need a profile and to login within the add-on user interface. Quick and painless, and if offers a free account type. A lot of good free assets available with a simple drag and drop into your scene.
https://www.blenderkit.com/get-blenderkit/
Extra Lights – Photometric Lighting For Blender
I use this when I am creating interior designs. It allows you to more easily add familiar lights to your scene, using spec like lumen and colour temp. I believe the color temperature is a bit off, but that is an easy fix (I will try to do some testing one day).
This is a reasonably priced add-on available from Blender Market: https://blendermarket.com/products/extra-lights
Node Wrangler
Everyone knows about this built-in add-on, however it needs to be manually enabled. It will likely make your work with shaders much more efficient.
Move Origin
My latest free Blender add-on, makes moving the origin of currently selected object(s) to the center-point of the selection—works with vertices, edges, faces and objects.
https://github.com/Gatada/JB-MoveOrigin
I am sure there are more, but that is all for now.
Johan