Huseyin Berberoglu

Allows users to add favorite posts. This plugin use cookies and database for 
saving data.
<ul>
<li>If a user logged in then favorites data will saved in database instead of cookies.</li>
<li>If user not logged in data will saved in cookies.</li>
</ul>
You can choose “only registered users can favorite a post” option, if you want. 
Also there is a widget named “Most Favorited Posts”. And you can use this template 
tag for listing most favorited posts;
Most Favorited Posts
If you use WP Super Cache you must add page (which you show favorites) URI to “Accepted Filenames & 
Rejected URIs”.
If you need support <a href="https://wordpress.org/support/plugin/wp-favorite-posts" rel="ugc">create a topic on support forum</a>
Please submit your pull requests to https://github.com/hberberoglu/wp-favorite-posts

WP Favorite Posts

Allows visitors to add favorite posts. This plugin use cookies for saving data so
unregistered users can favorite a post.

Takashi Matsuyama

Save user’s favorite posts and list them. 
This plugin is simple. You can save the user’s favorite posts just a install and display them anywhere you want with just a shortcode. 
The logged-in user’s data is saved in the user meta. Other user’s data is saved to Web Storage (localStorage).
<h3>Usage</h3>
<ul>
<li>Shortcode: <code>[ccc_my_favorite_select_button post_id="" style=""]</code></li>
<li>Shortcode: <code>[ccc_my_favorite_list_menu slug="" text="" style=""]</code></li>
<li>Shortcode: <code>[ccc_my_favorite_list_results class="" style=""]</code></li>
</ul>
For pages with a shortcode for list view ([ccc_my_favorite_list_results]).
“Load More” is displayed with “posts_per_page”. 
It will be displayed when the user has more favorite posts than “posts_per_page”.
<ul>
<li>Shortcode: <code>[ccc_my_favorite_list_results posts_per_page="10"]</code> default is 100 posts.</li>
</ul>
You can display the post’s “excerpt”. 
This value is the char length. 
If not needed, use “no excerpt” or “0”.
<ul>
<li>Shortcode: <code>[ccc_my_favorite_list_results excerpt="30"]</code></li>
</ul>
If you want, you can change the code for list view yourself.
<ul>
<li>Shortcode: <code>[ccc_my_favorite_list_custom_template style=""]</code></li>
</ul>
For pages with a shortcode for custom list view ([ccc_my_favorite_list_custom_template]). 
Add the function (<code>function ccc_my_favorite_list_custom_template( $my_favorite_post_id ) { }</code>) for your list view to <code>your-theme/functions.php</code>. 
 $my_favorite_post_id is array. 
 style=”none” excludes the default CSS for the list.
Detailed usage is under preparation.
<h3>Discover More</h3>
This plugin is <a href="https://github.com/takashi-matsuyama/my-favorites" rel="nofollow ugc">developed on GitHub</a>

My Favorites

Save user's favorite posts and list them.

WP Favorite Posts vs My Favorites