WP_Query::is_attachment()

Method: Is the query for an existing attachment page?

Source: wp-includes/class-wp-query.php:3420

WP_Query::is_robots()

Method: Is the query for the robots file?

Source: wp-includes/class-wp-query.php:3782

Method: Is the query for an existing author archive page?

Source: wp-includes/class-wp-query.php:3454

Method: Is the query for a search?

Source: wp-includes/class-wp-query.php:3793

Method: Is the query for an existing category archive page?

Source: wp-includes/class-wp-query.php:3486

Method: Is the query for an existing single post?

Source: wp-includes/class-wp-query.php:3813

Method: Is the query for an existing tag archive page?

Source: wp-includes/class-wp-query.php:3518

Method: Is the query for an existing single post of any post type (post, attachment, page, custom post types)?

Source: wp-includes/class-wp-query.php:3860

Method: Is the query for an existing custom taxonomy archive page?

Source: wp-includes/class-wp-query.php:3557

Method: Is the query for a specific time?

Source: wp-includes/class-wp-query.php:3876