Dana Ross

Widget that displays on your WordPress search results page with similar items from your Flickr, YouTube, and Twitter feeds.
For example, someone searching for “cat” on your site might see Flickr photos you’ve tagged with “cat”, or that funny YouTube video you took of your kitty the other day.
Currently searches: * Flickr * Twitter * YouTube
…or any combination of the above!
View the announcement for this plugin at http://www.slideshare.net/fvcp/wpexternalsearch

Dave’s External Search

Widget that displays on your WordPress search results page with similar items from your Flickr, YouTube, and Twitter feeds.

Sumit Chattha

This plugin is used to fetch Youtube Videos, Vimeo Videos, Images and create post to specific category. 
Admin can choose categories and Twitter and Pinterest account to share the posts on both the social media account at once.
For more details go through the link http://www.viralsoftwares.com/viralism

Viralism

Fetch Viral videos/images and create automated post.

Dave’s External Search vs Viralism