field_get_items.php

<?php

// Proper way to get the value of a field i18n safe.
if ($field = field_get_items('node', $variables['node'], 'field_my_field')) {
    $variables['custom_var'] = $field[0]['value'];
}

file_entity_view_modes.php

<?php

/**
 * Implements hook_entity_info_alter().
 *
 * Add new view modes to file entities.
 */
function HOOK_entity_info_alter(&$entity_info) {
  $entity_info['file']['view modes']['media_slideshow'] = array(
    'label' => t('Slideshow'),
    'custom settings' => TRUE,
  );
  $entity_info['file']['view modes']['media_colorbox'] = array(
    'label' => t('Colorbox'),
    'custom settings' => TRUE,
  );
  $entity_info['file']['view modes']['media_wide'] = array(
    'label' => t('Wide'),
    'custom settings' => TRUE,
  );
  $entity_info['file']['view modes']['media_gallery'] = array(
    'label' => t('Gallery'),
    'custom settings' => TRUE,
  );
}

gistfile1.aw

<?php

/**
 * Add a stylesheet to the admin theme
 */
function HOOK_preprocess_page(&$variables) {
  global $theme_info;

  // If the page load is for the admin theme
  if ($theme_info->name == variable_get('admin_theme')) {
    drupal_add_css(drupal_get_path('theme', 'MYTHEME') . '/stylesheets/seven.css', array(
      'group' => CSS_THEME,
    ));
  }
}

hide_toolbar.php

<?php

/**
 * Implements hook_page_alter().
 *
 * Hides the administration toolbar if the administration menu is available.
 */
function HOOK_page_alter(&$page) {
  // Hide Toolbar for those who can access the admin menu.
  if (user_access('access administration menu') && !empty($page['page_top']['toolbar'])) {
    $page['page_top']['toolbar']['#access'] = FALSE;
  }
}

hook_css_alter.php

<?php

/**
 * Implements hook_css_alter().
 *
 * Remove core stylesheets
 */
function HOOK_css_alter(&$css) {
  $exclude = array(
    #'misc/vertical-tabs.css' => FALSE,
    #'modules/aggregator/aggregator.css' => FALSE,
    #'modules/block/block.css' => FALSE,
    #'modules/book/book.css' => FALSE,
    #'modules/comment/comment.css' => FALSE,
    #'modules/dblog/dblog.css' => FALSE,
    #'modules/file/file.css' => FALSE,
    #'modules/filter/filter.css' => FALSE,
    #'modules/forum/forum.css' => FALSE,
    #'modules/help/help.css' => FALSE,
    #'modules/menu/menu.css' => FALSE,
    #'modules/node/node.css' => FALSE,
    #'modules/openid/openid.css' => FALSE,
    #'modules/poll/poll.css' => FALSE,
    #'modules/profile/profile.css' => FALSE,
    #'modules/search/search.css' => FALSE,
    #'modules/statistics/statistics.css' => FALSE,
    #'modules/syslog/syslog.css' => FALSE,
    #'modules/system/admin.css' => FALSE,
    #'modules/system/maintenance.css' => FALSE,
    #'modules/system/system.admin.css' => FALSE,
    'modules/system/system.base.css' => FALSE,
    #'modules/system/system.maintenance.css' => FALSE,
    'modules/system/system.menus.css' => FALSE,
    'modules/system/system.messages.css' => FALSE,
    'modules/system/system.theme.css' => FALSE,
    #'modules/taxonomy/taxonomy.css' => FALSE,
    #'modules/tracker/tracker.css' => FALSE,
    #'modules/update/update.css' => FALSE,
    #'modules/user/user.css' => FALSE,
  );
  $css = array_diff_key($css, $exclude);
}

HOOK_form_user_login_alter.php

<?php

/**
 * Implements hook_form_alter().
 *
 * Redirects user logins to the front page.
 */
function HOOK_form_user_login_alter(&$form, &$form_state) {
  $form['#action'] = url('user', array('query' => array('destination' => '<front>')));
}  

hook_js_alter.php

<?php

/**
 * Implements hook_js_alter().
 *
 * Remove core js files
 */
function HOOK_js_alter(&$javascript) {
  $exclude = array(
    'misc/textarea.js' => FALSE,
  );
  $javascript = array_diff_key($javascript, $exclude);
}

invisimail_encode_email.php

<?php

// Encode email address with invisimail module
$email = variable_get('site_mail', '');
if (module_exists('invisimail')) {
  $email = invisimail_encode_email($email, 'html_entities', array('link' => TRUE));
}

long_block_titles.php

<?php

/**
 * Implements hook_form_alter().
 *
 * Allow for 128 length block titles.
 * You also need to edit the SQL table `blocks` column `title` to VARCHAR( 128 ).
 */
function HOOK_form_alter(&$form, &$form_state, $form_id) {
  // Allow long titles
  if (isset($form['module']['#value']) && $form['module']['#value'] == "block") {
    $form['settings']['title']['#maxlength'] = 128;
  }
}

theme_hook_suggestions.php

<?php

function THEME_preprocess_node(&$variables) {
  // Add theme suggestion for teasers
  if ($variables['teaser']) {
    $variables['theme_hook_suggestions'][] = 'node__teaser';
  }

  // Add content type specific suggestions for teasers
  if ($variables['teaser'] && $variables['type']){
    $variables['theme_hook_suggestions'][] = 'node__'. $variables['type'] .'__teaser';
  }
}