I grabbed the RSS aggregator from the Dashboard and, with the help of another topic in this support forum (thanks for telling me about that require_once
business), here you go:
<?php
require_once (ABSPATH . WPINC . '/rss-functions.php');
// change this to whatever feed you want displayed
$rss = @fetch_rss('https://planet.www.ads-software.com/feed/');
if ( isset($rss->items) && 0 != count($rss->items) ) {
// change this to whatever you want it titled
?>
<h3><?php _e('Other WordPress News'); ?> <a href="https://planet.www.ads-software.com/"><?php _e('more'); ?> »</a></h3>
<ul>
<?php
// change the number "20" to the number of items you want displayed
$rss->items = array_slice($rss->items, 0, 20);
foreach ($rss->items as $item ) {
?>
<li><a href='<?php echo wp_filter_kses($item['link']); ?>'><?php echo wp_specialchars($item['title']); ?></a></li>
<?php
}
?>
</ul>
<?php
}
?>
If you use something that will combine all of your various feeds into one (https://feedjumbler.com/, https://www.rssmix.com/, do a Google search for it), you should be pretty well set.
Yet another post here on the forum might provide even more answers.