mrzerog

WP Favorites allows your logged in users to favorite a tag, and allows them to see only posts that have that tag. They can also favorite multiple tags, and see only posts that have all those tags (or optionally any post with any of those tags). Example: You run a site about tea, iced and hot, green black and white. You tag every post green, black, or white, as well as iced or hot. Your user only likes iced green tea, so they favorite the ‘iced’ tag, and the ‘green’ tag. Then, they can see only posts pertaining to iced green tea (or optionally any post’s tagged either iced or green). Users are able to favorite a tag from it’s archive page.

wp_favorites

wp_favorites allows a logged in user to favorite a tag or tags and then show only posts that have that tag or a combination of those tags

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.

wp_favorites vs WP Favorite Posts