shprung

Less than 40 lines of php code so it will not slow your site and if all you 
need is to add an rss feed, give it a try.
You can even setup the output template – something many other plugin don’t 
offer.
<h3>A brief Markdown Example</h3>
<pre><code>short code examples:

[rss url="http://www.usacycling.org/rss/headlines.rss"]


[rss url="http://www.usacycling.org/rss/headlines.rss" no="20" target="_self"]

You can change the template used via wp-admin/options.php , look for
'rss_shortcode_template'
Template fields documentation:
 _TITLE_ : the rss feed title line
 _LINK_ : the link to the complete store, aka permalink
 _MSG_ : the short message/description; the first few 
 lines of the post/story
 _DATE_ : post date & time
 _TARGET_ : the link target
</code></pre>

RSS shortcode w/template

lets you embed rss feed in any WordPress content (e.g., pages, posts, custom post types) using Shortcode.

GNPublisher

GN Publisher makes RSS feeds that comply with the <a href="https://support.google.com/news/publisher-center/answer/9545420" rel="nofollow ugc">Google News RSS Feed Technical Requirements</a> for including your site in the <a href="https://publishercenter.google.com/" rel="nofollow ugc">Google News Publisher Center</a>.
The plugin addresses common RSS compatiblity issues publishers experience when using the Google News Publisher Center, including:
<ul>
<li>Incomplete articles</li>
<li>Duplicate images</li>
<li>Missing images or media</li>
<li>Missing content (usually social media/Instagram embeds)</li>
<li>Title errors (missing or repeated titles)</li>
<li>Cached RSS feeds causing slow updating</li>
<li>Delayed crawling by Google</li>
</ul>
After installing, click on the ‘Dashboard’ under GN Publisher on your plugins page for additional information about applying and troubleshooting issues related to the Google News Publisher Center.
New in 1.5.24 
Compatibility with Apple news publish
New in 1.5.11 
Google Reader Revenue Manager support.Reader Revenue Manager provides publisher solutions to deepen audience engagement and convert subscribers or contributors.
New in 1.0.9
GN Publisher now displays the time of the most recent ping and feed fetch from Google. This helps when troubleshooting the dreaded ’empty sections’ issue in the Google News Publisher Center.
New in 1.0.6
GN Publisher now pings Google when feeds are updated. This can help with faster updates in your Google News Publication.
<h3>Support</h3>
We try our best to provide support on <a href="https://wordpress.org/support/plugin/gn-publisher/" rel="ugc">WordPress GN Publisher plugin support forum</a> forums. However, We have a special <a href="https://gnpublisher.com/contact-us/" rel="nofollow ugc">team support</a> where you can ask us questions and get help. Delivering a good user experience means a lot to us and so we try our best to reply each and every question that gets asked.
<h3>Bug Reports</h3>
Bug reports for GN Publisher: Google News Compatible RSS Feeds are <a href="https://github.com/ahmedkaludi/gn-publisher/issues/" rel="nofollow ugc">welcomed on GitHub</a>. Please note GitHub is not a support forum, and issues that aren’t properly qualified as bugs will be closed.
<h3>PRO Version</h3>
Take you Google News Feed experience to next level by using our <a href="https://gnpublisher.com/pricing/#pricing" rel="nofollow ugc">GN Publisher PRO</a> plugin which contains the following features.
<ul>
<li>Content Scraping Protection </li>
<li>Exclude Categories From Main Feed </li>
<li>Google News Sitemap </li>
<li>Compatibility with Flipboard.com</li>
<li>Compatibility with PublishPress Authors</li>
<li>Compatibility with Translate Press</li>
</ul>

GN Publisher: Google News Compatible RSS Feeds

GN Publisher makes RSS feeds that comply with the Google News RSS Feed Technical Requirements for including your site in the Google News.

RSS shortcode w/template vs GN Publisher: Google News Compatible RSS Feeds