front-page.php – The front page template, it is only used if you use a static front page.
home.php – The home page template, which is the front page by default. If you use a static front page this is the template for the page with the latest posts.
single.php – The single post template. Used when a single post is queried. For this and all other query templates, index.php is used if the query template is not present.
single-.php – The single post template used when a single post from a custom post type is queried. For example, single-books.php would be used for displaying single posts from the custom post type books. index.php is used if the query template for the custom post type is not present.
page.php – The page template. Used when an individual Page is queried.
category.php – The category template. Used when a category is queried.
tag.php – The tag template. Used when a tag is queried.
taxonomy.php – The term template. Used when a term in a custom taxonomy is queried.
author.php – The author template. Used when an author is queried.
date.php – The date/time template. Used when a date or time is queried. Year, month, day, hour, minute, second.
archive.php – The archive template. Used when a category, author, or date is queried. Note that this template will be overridden by category.php, author.php, and date.php for their respective query types.
search.php – The search results template. Used when a search is performed.
attachment.php – Attachment template. Used when viewing a single attachment.
image.php – Image attachment template. Used when viewing a single image attachment. If not present, attachment.php will be used.