Code autocomplete greatly simplifies writing scripts or developing add-ons for Blender. One of the best autocomplete modules for today is developed by Nutti. Last updated 20190718.
The project is hosted on the author’s GitHub: https://github.com/nutti/fake-bpy-module
The modules are distributed via pip or as a pre-generated-modules. AuthorĀ also provides a module generator with which you can assemble autocomplete modules yourself.