Note: this list is generated by pattern matching, so it may include some functions that are not actually implementations of this hook.

block_add_block_form in modules/block/block.admin.inc
Menu callback: display the custom block addition form.
block_admin_display_form in modules/block/block.admin.inc
Generate main blocks administration form.
block_box_form in modules/block/block.module
Define the custom block form.
blog_form in modules/blog/blog.module
Implementation of hook_form().
book_outline_form in modules/book/book.pages.inc
Build the form to handle all book outline operations via the outline tab.
book_remove_form in modules/book/book.pages.inc
Menu callback; builds a form to confirm removal of a node from the book.
color_scheme_form in modules/color/color.module
Form callback. Returns the configuration form.
comment_form in modules/comment/comment.module
Generate the basic commenting form, for appending to a node or display on a separate page.
comment_unpublish_by_keyword_action_form in modules/comment/comment.module
Form builder; Prepare a form for blacklisted keywords.
confirm_form in modules/system/system.module
Generates a form array for a confirmation form.
dblog_filter_form in modules/dblog/dblog.admin.inc
Return form for dblog administration filters.
drupal_get_form in includes/form.inc
Retrieves a form from a constructor function, or from the cache if the form was built in a previous page-load. The form is then passed on for processing, after and rendered for display if necessary.
drupal_prepare_form in includes/form.inc
Prepares a structured form array by adding required elements, executing any hook_form_alter functions, and optionally inserting a validation token to prevent tampering.
drupal_process_form in includes/form.inc
This function is the heart of form API. The form gets built, validated and in appropriate cases, submitted.
drupal_rebuild_form in includes/form.inc
Retrieves a form, caches it and processes it with an empty $_POST.
drupal_redirect_form in includes/form.inc
Redirect the user to a URL after a form has been processed.
drupal_render_form in includes/form.inc
Renders a structured form array into themed HTML.
drupal_retrieve_form in includes/form.inc
Retrieves the structured array that defines a given form.
drupal_validate_form in includes/form.inc
Validates user-submitted form data from the $form_state using the validate functions defined in a structured form array.
example_form in developer/example.profile
Form API array definition for the example form.
filter_admin_format_form in modules/filter/filter.admin.inc
Generate a filter format form.
filter_form in modules/filter/filter.module
Generates a selector for choosing a format in a form.
forum_form in modules/forum/forum.module
Implementation of hook_form().
install_configure_form in ./install.php
Form API array definition for site configuration.
install_select_locale_form in ./install.php
Form API array definition for language selection.
install_select_profile_form in ./install.php
Form API array definition for the profile selection form.
install_settings_form in ./install.php
Form API array definition for install_settings.
locale_languages_configure_form in includes/locale.inc
Setting for language negotiation options
locale_languages_custom_form in includes/locale.inc
Custom language addition form.
locale_languages_delete_form in includes/locale.inc
User interface for the language deletion confirmation screen.
locale_languages_edit_form in includes/locale.inc
Editing screen for a particular language.
locale_languages_overview_form in includes/locale.inc
User interface for the language overview screen.
locale_languages_predefined_form in includes/locale.inc
Predefined language setup form.
locale_translate_delete_form in includes/locale.inc
User interface for the string deletion confirmation screen.
locale_translate_edit_form in includes/locale.inc
User interface for string editing.
locale_translate_export_pot_form in includes/locale.inc
Translation template export form.
locale_translate_export_po_form in includes/locale.inc
Form to export PO files for the languages provided.
locale_translate_import_form in includes/locale.inc
User interface for the translation import screen.
locale_translate_seek_form in includes/locale.inc
User interface for the string search screen.
menu_item_delete_form in modules/menu/menu.admin.inc
Build a confirm form for deletion of a single menu link.
menu_overview_form in modules/menu/menu.admin.inc
Form for editing an entire menu tree at once.
node_assign_owner_action_form in modules/node/node.module
node_content_form in modules/node/node.module
Implementation of hook_form().
node_filter_form in modules/node/node.admin.inc
Return form for node administration filters.
node_form in modules/node/node.pages.inc
Generate the node add/edit form array.
node_type_form in modules/node/content_types.inc
Generates the node type editing form.
node_unpublish_by_keyword_action_form in modules/node/node.module
openid_redirect_form in modules/openid/openid.inc
openid_user_delete_form in modules/openid/openid.pages.inc
Present a confirmation form to delete the specified OpenID identity from the system.
path_admin_filter_form in modules/path/path.admin.inc
Return a form to filter URL aliases.
path_admin_form in modules/path/path.admin.inc
Return a form for editing or creating an individual URL alias.
poll_cancel_form in modules/poll/poll.module
Builds the cancel form for a poll.
poll_form in modules/poll/poll.module
Implementation of hook_form().
profile_field_form in modules/profile/profile.admin.inc
Menu callback: Generate a form to add/edit a user profile field.
search_form in modules/search/search.module
Render a search form.
system_actions_delete_form in modules/system/system.module
Create the form for confirmation of deleting an action.
system_actions_manage_form in modules/system/system.module
Define the form for the actions overview page.
system_goto_action_form in modules/system/system.module
Implementation of a configurable Drupal action. Redirect user to a URL.
system_message_action_form in modules/system/system.module
system_modules_confirm_form in modules/system/system.admin.inc
Display confirmation form for dependencies.
system_modules_uninstall_confirm_form in modules/system/system.admin.inc
Confirm uninstall of selected modules.
system_send_email_action_form in modules/system/system.module
Return a form definition so the Send email action can be configured.
system_settings_form in modules/system/system.module
Add default buttons to a form and set its prefix.
system_themes_form in modules/system/system.admin.inc
Menu callback; displays a listing of all themes.
system_theme_select_form in modules/system/system.module
Returns a fieldset containing the theme select form.
taxonomy_form in modules/taxonomy/taxonomy.module
Generate a form element for selecting terms from a vocabulary.
template_preprocess_block_admin_display_form in modules/block/block.admin.inc
Process variables for block-admin-display.tpl.php.
template_preprocess_search_block_form in modules/search/search.module
Process variables for search-block-form.tpl.php.
template_preprocess_search_theme_form in modules/search/search.module
Process variables for search-theme-form.tpl.php.
theme_block_admin_display_form in developer/theme.php
Implemented using the block-admin-display-form.tpl.php template.
theme_color_scheme_form in modules/color/color.module
Theme color form.
theme_form in includes/form.inc
Format a form.
theme_locale_languages_overview_form in includes/locale.inc
Theme the language overview form.
theme_menu_overview_form in modules/menu/menu.admin.inc
Theme the menu overview form into a table.
theme_node_filter_form in modules/node/node.admin.inc
Theme node administration filter form.
theme_node_form in modules/node/node.pages.inc
Present a node submission form.
theme_search_block_form in developer/theme.php
Implemented using the search-block-form.tpl.php template.
theme_search_theme_form in developer/theme.php
Implemented using the search-theme-form.tpl.php template.
theme_system_themes_form in modules/system/system.admin.inc
Theme function for the system themes form.
theme_system_theme_select_form in modules/system/system.admin.inc
Theme the theme select form.
theme_user_filter_form in modules/user/user.admin.inc
Theme user administration filter form.
trigger_assign_form in modules/trigger/trigger.admin.inc
Create the form definition for assigning an action to a hook-op combination.
update_script_selection_form in ./update.php
user_admin_access_form in modules/user/user.admin.inc
Form builder; Configure access rules.
user_edit_form in modules/user/user.module
user_filter_form in modules/user/user.admin.inc
Form builder; Return form for user administration filters.
user_profile_form in modules/user/user.pages.inc
Form builder; edit a user account or one of their profile categories.