Ruven

This plugin registers a custom post type for portfolio items and a taxonomy for portfolio types.
Selected themes by Ruven provide templates to display portfolio items. 
In other themes you most likely have to add them by yourself.

Ruven Themes: Portfolio

RT Portfolio enables a "Portfolio" post type and "Type" taxonomy.

Bobby Gunawan

A plugin which adds portfolio custom post type for WordPress themes <a href="https://made4wp.com" rel="nofollow ugc">by Made4WP</a>.
This plugin adds a custom post type “portfolio” and other portfolio related backend features like taxonomies and meta boxes.
This plugin DOES NOT add any front end display. You will need to add/edit your own “single-portfolio.php”, “archive-portfolio.php” or make a custom query for the post type “portfolio” to display the portfolio items.
Although this plugin is meant to be used with Made4WP themes, please feel free to use it for your own themes as well.
** UPDATE NOTICE ** 
The taxonomy “type” has been changed to “category”. If you had any portfolio items using the type taxonomy, you will need to recreate and switch them to use categories instead.

M4WP Portfolio

A Made4WP plugin. This plugin adds the custom post type "Portfolio" and it's related features such as taxonomies or meta boxes.

Ruven Themes: Portfolio vs M4WP Portfolio