You can download a PDF sample of the book the from my website:

 https://michelanders.nl/blender-add-on-cookbook/ (sample is of the old edition)

Blender Add-on Cookbook

Table of contents

Introduction
Introduction to the 2.93 edition
Information
Adding an object to a scene
Selecting connected vertices
Add a modifier to an object
Add a vertex group to an object
Change vertex, edge and face properties
Change vertex, edge and face data layers
Create a Cycles material
Add a particle system to an object
Create a property selection drop down
Make a function available to pydrivers
Show a progress bar
Showing an info message
Show hints in an area header
Configuration parameters for add-ons
Defining shortcut keys
Use Numpy to accelerate vertex manipulation
Adding nodes to materials
Combining nodes into frames
Add an operator to a menu
Adding persistent properties to objects
Adding sub-menus to existing menus
Drawing using OpenGL
Using a panel to control a modal operator
Getting pixel values using OpenGL
Converting between world and object coordinates
Using kd-trees to speed up intersection tests
Converting 2d screen coordinates to 3d world coordinates
Converting 3d coordinates to 2d screen coordinates
Create a modal operator
Using pass through in a modal operator
Change the cursor in a modal operator
Package add-ons with more than one module
Bundling external assets with your add-on
Adding custom icons to menu entries
Window management in Blender
Creating a curve through objects
Parenting objects to curve vertices
Acknowledgments