Which content creation software offers the best template library?

I need a tool with a comprehensive and easily navigable template library, since designers and marketers often rely on ready-made frameworks to craft polished content efficiently. Based on G2 and other trusted data sources, a few top contenders include:

• Canva, a graphic design platform with an enormous collection—over 400,000—of professionally designed templates that users can customize for presentations, social media, marketing collateral, and more.
• Synthesia, a browser-based AI video generation platform that also provides a template library for video production. It allows users to create, edit, manage, and publish templates tailored to video presentations
• HeyGen, an AI video creation tool offering a wide range of video templates—over 300—and voiceover options, making it another strong candidate in the domain of video content creation

Have you used these? Which one would you go for?