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.

Gary Jones

Devin Price

This plugin registers a custom post type for portfolio items. It also registers separate portfolio taxonomies for tags and categories. If featured images are selected, they will be displayed in the column view.
This plugin doesn’t change how portfolio items are displayed in your theme. You’ll need to add templates for archive-portfolio.php and single-portfolio.php if you want to customize the display of portfolio items.

Portfolio Post Type

This plugin registers a custom post type for portfolio items.  It also registers separate portfolio taxonomies for tags and categories.

Ruven Themes: Portfolio vs Portfolio Post Type