Marco Brughi

This plugin create a widget to set the reading of RSS. It works with both RSS and XML. There are a few parameters to set up: Title = The title to display in your blog, RSS Feed = The URL of your selected RSS (work both rss or xml feed), Item to display = how many item display (from 1 to 5), show date = y/n, show summary = y/n.

RSS Advanced Widget

Create a widget to set the reading of RSS. It works with both RSS and XML. Easy to install and set up, just enter the URL of the desired RSS.

Marcin Pietrzak

Allow to publish post thumbnails on sidebar and on RSS.
Other plugins by iworks: <a href="https://wordpress.org/extend/plugins/tag-list/" rel="ugc">Tag list</a>, <a href="https://wordpress.org/extend/plugins/auto-referrer/" rel="ugc">AutoReferrer</a>, <a href="https://wordpress.org/extend/plugins/flakuj/" rel="ugc">flakuj</a>.
<h3>Localizations</h3>
<ul>
<li>Polish (pl_PL) – <a href="http://iworks.pl/" rel="nofollow ugc">Marcin Pietrzak</a></li>
</ul>
If you have created your own language pack, or have an update of an existing one, you can send <a href="https://codex.wordpress.org/Translating_WordPress" rel="nofollow ugc">gettext PO and MO files</a> to me so that I can bundle it into Tag list. You can <a href="https://wordpress.org/extend/plugins/post-thumbnail-widget/admin/post-thumbnail-widget.pot" rel="ugc">download the latest POT file from here</a>.

Post Thumbnail Widget

Allow to publish post thumbnails on sidebar and on RSS.

RSS Advanced Widget vs Post Thumbnail Widget