Set the Featured Image Automatically
When a post is saved without a featured image, uses the first image attached to it or the first image block in its content.
Snippet Library
Content snippets for WordPress
Snippets that add to or change your posts and pages: reading time, author boxes, “last updated” notes, content after the post or after a paragraph, and excerpt tweaks. For bloggers, publishers and anyone who wants richer posts without editing theme files.