Here is the list of popular wordpress php hooks. You can use these hooks to display various elements on different parts of the web page.
Theme Hooks
<?php get_header(); ?>
<?php the_post(); ?>
<?php the_content(); ?>
<?php get_footer(); ?>
<?php comments_template(); ?>
<?php get_sidebar(); ?>
<?php the_author_posts_link(); ?>
<?php get_search_form(); ?>
<?php the_excerpt(); ?>
<?php echo bloginfo('description'); ?>
<?php the_widget( 'WP_Widget_Recent_Posts', '', $args ); ?>
<?php the_widget( 'WP_Widget_Recent_Posts', '', $args ); ?>
<?php the_widget( 'WP_Widget_Archives', 'dropdown=1', $args ); ?>
<?php the_widget( 'WP_Widget_Categories', 'dropdown=1', $args ); ?>
<?php the_widget( 'WP_Widget_Tag_Cloud', '', $args ); ?>
<?php the_widget( 'WP_Widget_Pages', '', $args ); ?>
Please let us know if you know any more hooks.