DECALmachine tries to work seamlessly with as many other addons as possible.
GroupPro makes working with huge scenes and lots of objects easy and unlocks the potential of collection instances in Blender.
Batch Ops™2 is a highly sophisticated data manager. It can outline/arrange/control all your modifiers, materials, collections (and other data) in the currently open file, scene or among the visible objects.
Hard Ops is a toolkit aimed at assisting users with everything from modelling to rendering, with a focus on hard surface design.
MACHIN3tools is a free, continuously evolving collection of blender tools and pie menus in a single customizable package.