kamiel79

Adding explicit thumbnails (featured images) to your content takes time. Even if you don’t add your own photography, you’d still need to go to search.creativecommons.org or so. This plugin hooks into the thumbnail URL and changes this with an image from the Flickr API, based on the tags in your post. If Flickr couldn’t find anything, it will return an empty string. I have achieved good results, with posts that all of a sudden had a rather adequate thumbnail.
[Flickr images might have licensing issues, so I recommend to use this plugin only on personal sites]

Flickr Fallback Thumbnail

Automatically grab a fallback featured image if your post doesn't have one!

Earl Evan Amante

A straight forward Posts Generator for Developers and Testers. 
Once active, a Posts Generator user will be created for later use.
In the Tools page, you can set the Title, Content, Post Type and number of posts to be generated. 
Once you’re done with the data, you may then delete the user since all generated posts will be under the Posts Generator user.

Simple Posts Generator

A straight forward Posts Generator for Developers and Testers.

Flickr Fallback Thumbnail vs Simple Posts Generator