nosoycesaros

A WordPress plugin designed to mark posts by logged in users. Allows theme developers and administrators create and edit post flags, like favorites, seen, likes, etc, also provides an easy way to put this flags in your theme via shortcode.
Features:
<ul>
<li>Administrators can create flags like ‘Favorites’, ‘Seen’ or ‘Bookmark’ for early use</li>
<li>You can create as many flags as you want</li>
<li>Allows customization of HTML code for each flag</li>
<li>Insert in themes and post via <code>[shortcode]</code></li>
<li>This plugin creates favorite flag and button by default</li>
</ul>

Post Flagger

Add Favorite or any flag button to your posts. The easy way

julienvdg

hreflang Flag plugin uses <a href="http://www.w3.org/TR/css3-selectors/#attribute-selectors" title="W3C CSS3 Attribute selectors description" rel="nofollow ugc">css3 selectors</a> to add a flag icon to your links depending on their <a href="http://www.w3.org/TR/html401/struct/links.html#adef-hreflang" title="hreflang attribute description on W3C" rel="nofollow ugc">hreflang attribute</a>.
This is really useful if you regularly link to pages in other languages and you want to inform your visitors about the language of the link target.
It’s even more useful if your own blog is multilingual.

hreflang Flag

Add a flag icon to link corresponding to the hreflang attribute.

Post Flagger vs hreflang Flag