oltdev

This plugin aggregates multiple blog(s) into one 
single blog. The imported blogs must be in the same WPMU installation 
as the destination blog. Suitable for WordPress MU only.
<h3>How to</h3>
<ol>
<li>
Using your favorite text editor, create a .txt file with all the 
links of the blog you wish to import. Separate each blog in new line. 
You can name it anything you want. Here’s an example.
https://wordpress.org/blog1/ 
https://wordpress.org/blog2/ 
https://wordpress.org/blog3/
</li>
<li>
From the menu you can choose to specify categories and tags filter. 
You can have multiple filter in one line. They are comma seperated.
</li>
<li>
Click on import button and begin the import.
</li>
</ol>

Multiple Import

Aggregate multiple blog(s) into one single blog.

sharespring

ShareSpring is a service that finds great user-generated content and embeds a beautiful gallery of the best posts onto your website.
Search for posts on Twitter, Instagram, Facebook, YouTube, and RSS. Pick which posts to embed on your website.
Display your own posts from all of your social networks, or find public posts, or mix everything together.

Multiple Import vs ShareSpring