Below is the list of some of the mostly used or needed functions while customizing the wordpress theme. Though its not the complete list I’ll be adding in coming days:

Author Template Tags

Author  - the_author();

Author Description  - the_author_description();

Author Login  - the_author_login();

Author First Name  - the_author_firstname();

Author Last Name  - the_author_lastname();

Author Nickname  - the_author_nickname();

Author ID  - the_author_ID();

Author Email - the_author_email();

Author Website URL - the_author_url();

Author Link - the_author_link();

Author AIM Screenname - the_author_aim();

Author Yahoo IM ID - the_author_yim();

Author Posts - the_author_posts();

Author Posts Link - the_author_posts_link();

Author List - wp_list_authors();

Category Template Tags

Post Category - the_category();

Post Category in RSS Format - the_category_rss();

Page Category Title - single_cat_title();

Category Description - category_description();

Category Dropdown - wp_dropdown_categories(‘arguments’);

Category Link List - wp_list_categories();

If In Category - in_category();

Category’s Parents List - get_category_parents();

Category Array - get_the_category();

Comment Template Tags

Comment Count - comments_number();

Link to Post Comments - comments_link();

Link to RSS Feed of Post Comments - comments_rss_link();

JavaScript for Pop-Up Window - comments_popup_script();

Link to Pop-Up Window - comments_popup_script();

Comment ID - comment_ID();

Author of Comment - comment_author();

IP Address of Comment Author - comment_author_IP();

Email of Comment Author - comment_author_email();

Website URL of Comment Author - comment_author_url();

Mailto Link to Comment Author - comment_author_email_link();

Link to Website URL of Comment Author - comment_author_link();

Type of Comment - comment_type();

Comment Text - comment_text();

Comment Excerpt - comment_excerpt();

Date of Comment - comment_date();

Time of Comment - comment_time();

Comment Author’s Name Formatted for RSS - comment_author_rss();

Comment Text Formatted for RSS - comment_text_rss();

Comment Link Formatted for RSS - comment_link_rss();

Comment Permalink Formatted for RSS - permalink_comments_rss();

Date & Time Template Tags

Post Date (xml) - the_date_xml();

Post Date - the_date();

Post Time - the_time();

Date (and Time) of Last Modification to Post - the_modified_date();

Time (and Date) of Last Modification to Post - the_modified_time();

Post Time (PHP) - get_the_time();

Current Page Month & Year Title - single_month_title();

Post Calendar - get_calendar();

General Template Tags

Blog Info - bloginfo();

Blog Info RSS - bloginfo_rss();

Blog Info (PHP) - get_bloginfo();

Blog Info RSS (PHP) - get_bloginfo_rss();

Page Title - wp_title();

Get Posts - get_posts;

Archives List - wp_get_archives();

Page Link List - wp_list_pages();

Page Dropdown - wp_dropdown_pages();

Login/Logout Link - wp_loginout();

Register/Site Admin Link - wp_register();

Query Posts - query_posts();

RSS Enclosures - rss_enclosure();

Tag Cloud - wp_tag_cloud();

Search Query - the_search_query();

Link Template Tags

‘Edit Post’ Link - edit_post_link();

‘Edit Comment’ Link - edit_comment_link();

Page Links - wp_page_links();

Yearly Archive URL - get_year_link();

Monthly Archive URL - get_month_link();

Daily Archive URL - get_day_link();

Previous Post Links - next_posts_link();

Permalink Template Tags

Permalink Anchor - permalink_anchor();

Permalink (PHP) - get_permalink();

Permalink URL - the_permalink();

Permalink (formatted for syndication feeds) - permalink_single_rss();

Post Template Tags

Post ID - the_ID();

Post Title - the_title();

Post Title (Attribute) - the_title_attribute();

Single Post Title - single_post_title();

Post Title (RSS) - the_title_rss();

Post Content - the_content();

Post Content (RSS) - the_content_rss();

Post Excerpt - the_excerpt();

Post Excerpt (RSS) - the_excerpt_rss();

Previous Post Link - previous_post_link();

Next Post Link - next_post_link();

Post Nav Links - posts_nav_link();

Post Meta - the_meta();

Post Tags - the_tags();

Post Count - wp_count_posts();