Here books about ideation. I've added their description below the titles. The first one is about using games for ideation, the second one about using questions, and the  last one about how to use constraints to get better ideas.

Gamestorming: A Playbook for Innovators, Rule-breakers, and Changemakers

Great things don't happen in a vacuum. But creating an environment for creative thinking and innovation can be a daunting challenge. How can you make it happen at your company? The answer may surprise you: gamestorming.
This book includes more than 80 games to help you break down barriers, communicate better, and generate new ideas, insights, and strategies.

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A More Beautiful Question: The Power of Inquiry to Spark Breakthrough Ideas

In this groundbreaking book, journalist and innovation expert Warren Berger shows that one of the most powerful forces for igniting change in business and in our daily lives is a simple, under-appreciated tool—one that has been available to us since childhood. Questioning—deeply, imaginatively, "beautifully"—can help us identify and solve problems, come up with game-changing ideas, and pursue fresh opportunities. So why are we often reluctant to ask "Why?"

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Inside the Box: A Proven System of Creativity for Breakthrough Results

Want to be creative? Then think Inside the Box. The traditional view says that creativity is unstructured and doesn’t follow rules or patterns. That you need to think “outside the box” to be truly original and innovative. That you should start with a problem and then “brainstorm” ideas without restraint until you find a solution. Inside the Box shows that more innovation— and better and quicker innovation—happens when you work inside your familiar world (yes, inside the box) using a set of templates that channel the creative process in a way that makes us more—not less—creative.

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