Helper fields play an essential role, especially on back office pages. There's a plenitude of them.

• Helper field 'bool'
• Helper field 'checkbox'
• Helper field 'code'
• Helper field 'color'
• Helper field 'email'
• Helper field 'file'
• Helper Field 'hidden'
• Helper field 'maintenance_ip'
• Helper field 'password'
• Helper field 'price'
• Helper field 'radio'
• Helper Field 'select'
• Helper field 'selectLang'
• Helper field 'tags'
• Helper Field 'text'
• Helper field 'textLang'
• Helper field 'textarea'
• Helper field 'textareaLang'

• Look up admin-dev/themes/default/template/helpers/options/options.tpl and search for $field['type'].
• Look up classes/helper/HelperOptions.php and search for $field['type'].
• PS documentation. A bit dated, but still close. Before documenting this, please exercise sample code and look up helper.tpl and HelperOptions.php for the details.

• Look up admin-dev/themes/default/template/helpers/options/options.tpl and search for $field in sections selected by $field['type'].
• Look up classes/helper/HelperOptions.php and search for $field.
• Look up AdminController->processUpdateOptions() and search for $values and $options.
• PS documentation.