Branding agency Bold has made several free styleguide templates available to download in InDesign format. Check them out.
70+ Brand Guidelines Templates, Examples & Tips - Venngage
Free Brand Guidelines Template (+ Best Tips), Easily Customizable
Brand Guidelines Template designs, themes, templates and
Brand style guide template Vectors & Illustrations for Free
Free customizable brand guidelines presentation templates
Freebie: Brand Style Guide Template - Every-Tuesday
Brand Guideline Template Style Guide Book Brochure Layout Manual
Free Brand Guidelines Templates
Free Vector Brand style guide template
4,293 Brand Style Guide Royalty-Free Images, Stock Photos
What is a Style Guide or Brand Guide? - Stellen Design