Adobe Express

Adobe Express (formerly Adobe Spark) is a free, browser-based design tool that handles graphics, video, and web pages without requiring Photoshop skills. You can create course thumbnails, social graphics, short videos, and landing pages using templates and AI design suggestions. It's not a full course authoring platform, but it's the fastest way to produce professional-looking visual assets for your courses.

This fits course creators who need polished visuals but aren't designers themselves, and organizations who want to keep production costs down. The free tier is surprisingly capable, and the integration with Adobe's stock library means you're not starting from scratch each time.