WordPress contains the roles Administrator, Editor, Author and Contributor which gives the following capabilities:
Administrator
■ activate_plugins
■ add_users
■ create_users
■ delete_others_pages
■ delete_others_posts
■ delete_pages
■ delete_plugins
■ delete_posts
■ delete_private_pages
■ delete_private_posts
■ delete_published_pages
■ delete_published_posts
■ delete_themes
■ delete_users
■ edit_dashboard
■ edit_files
■ edit_others_pages
■ edit_others_posts
■ edit_pages
■ edit_plugins
■ edit_posts
■ edit_private_pages
■ edit_private_posts
■ edit_published_pages
■ edit_published_posts
■ edit_theme_options
■ edit_themes
■ edit_users
■ export
■ import
■ install_plugins
■ install_themes
■ list_users
■ manage_categories
■ manage_links
■ manage_options
■ moderate_comments
■ promote_users
■ publish_pages
■ publish_posts
■ read_private_pages
■ read_private_posts
■ read
■ remove_users
■ switch_themes
■ unfiltered_html
■ unfiltered_upload
■ update_core
■ update_plugins
■ update_themes
■ upload_files
Editor
■ delete_others_pages
■ delete_others_posts
■ delete_pages
■ delete_posts
■ delete_private_pages
■ delete_private_posts
■ delete_published_pages
■ delete_published_posts
■ edit_others_pages
■ edit_others_posts
■ edit_pages
■ edit_posts
■ edit_private_pages
■ edit_private_posts
■ edit_published_pages
■ edit_published_posts
■ manage_categories
■ manage_links
■ moderate_comments
■ publish_pages
■ publish_posts
■ read
■ read_private_pages
■ read_private_posts
■ unfiltered_html
■ upload_files
Author
■ delete_posts
■ delete_published_posts
■ edit_posts
■ edit_published_posts
■ publish_posts
■ read
■ upload_files
Contributor
■ delete_posts
■ edit_posts
■ read
For more further details see WordPress Codex here.
