Prasanna SP

Just like the normal WordPress site feed, wordpress categories and tags also has feeds. The category feed is located at <code>site.url/category/categoryname/feed</code>. This plugin automatically adds the RSS feed link to the current post categories after the post content. By default the plugin shows category feed link on single posts. You can change it’s settings to show it on other pages, such as archives as well. You can change it’s title in WP-Admin –> Settings –> Follow Category Feeds.
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Follow WordPress Category Feeds

This plugin adds link for the category feeds after post content.

zackproser

The Simple Twitter Follow Me button allows you to add a small or large Twitter follow button to the end of every post so you can grow your Twitter following with your blog readers and let your audience easily share your content on social networks.
Once installed and activated, go to Settings -> Reading and scroll down to the Simple Twitter Follow Button settings.
Here you can enter your Twitter username and choose whether the button should be small or large.

Simple Twitter Follow Me Button

This plugin is the easiest way to add an official Twitter follow button at the end of every post so your readers can follow you on Twitter.

Follow WordPress Category Feeds vs Simple Twitter Follow Me Button