diff --git a/core/themes/classy/templates/breadcrumb.html.twig b/core/themes/classy/templates/breadcrumb.html.twig
new file mode 100644
index 0000000..f6a1705
--- /dev/null
+++ b/core/themes/classy/templates/breadcrumb.html.twig
@@ -0,0 +1,27 @@
+{#
+/**
+ * @file
+ * Default theme implementation for a breadcrumb trail.
+ *
+ * Available variables:
+ * - breadcrumb: Breadcrumb trail items.
+ *
+ * @ingroup themeable
+ */
+#}
+{% if breadcrumb %}
+  <nav class="breadcrumb" role="navigation" aria-labelledby="system-breadcrumb">
+    <h2 id="system-breadcrumb" class="visually-hidden">{{ 'Breadcrumb'|t }}</h2>
+    <ol>
+    {% for item in breadcrumb %}
+      <li>
+        {% if item.url %}
+          <a href="{{ item.url }}">{{ item.text }}</a>
+        {% else %}
+          {{ item.text }}
+        {% endif %}
+      </li>
+    {% endfor %}
+    </ol>
+  </nav>
+{% endif %}
diff --git a/core/themes/classy/templates/checkboxes.html.twig b/core/themes/classy/templates/checkboxes.html.twig
new file mode 100644
index 0000000..7c56355
--- /dev/null
+++ b/core/themes/classy/templates/checkboxes.html.twig
@@ -0,0 +1,17 @@
+{#
+/**
+ * @file
+ * Default theme implementation for a 'checkboxes' #type form element.
+ *
+ * Available variables
+ * - attributes: A list of HTML attributes for the wrapper element.
+ * - children: The rendered checkboxes.
+ *
+ * @see template_preprocess_checkboxes()
+ *
+ * @ingroup themeable
+ */
+ @todo: remove this file once http://drupal.org/node/1819284 is resolved.
+ This is identical to core/modules/system/templates/container.html.twig
+#}
+<div{{ attributes.addClass('form-checkboxes') }}>{{ children }}</div>
diff --git a/core/themes/classy/templates/confirm-form.html.twig b/core/themes/classy/templates/confirm-form.html.twig
new file mode 100644
index 0000000..d714917
--- /dev/null
+++ b/core/themes/classy/templates/confirm-form.html.twig
@@ -0,0 +1,15 @@
+{#
+/**
+ * @file
+ * Default theme implementation for confirm form.
+ *
+ * By default this does not alter the appearance of a form at all,
+ * but is provided as a convenience for themers.
+ *
+ * Available variables:
+ * - form: The confirm form.
+ *
+ * @ingroup themeable
+ */
+#}
+{{ form }}
diff --git a/core/themes/classy/templates/container.html.twig b/core/themes/classy/templates/container.html.twig
new file mode 100644
index 0000000..6fb8159
--- /dev/null
+++ b/core/themes/classy/templates/container.html.twig
@@ -0,0 +1,20 @@
+{#
+/**
+ * @file
+ * Default theme implementation of a container used to wrap child elements.
+ *
+ * Used for grouped form items. Can also be used as a #theme_wrapper for any
+ * renderable element, to surround it with a <div> and HTML attributes.
+ *
+ * Available variables:
+ * - attributes: HTML attributes for the containing element.
+ * - children: The rendered child elements of the container.
+ * - has_parent: A flag to indicate that the container has one or more parent
+     containers.
+ *
+ * @see template_preprocess_container()
+ *
+ * @ingroup themeable
+ */
+#}
+<div{{ attributes.addClass(has_parent ? 'form-wrapper') }}>{{ children }}</div>
diff --git a/core/themes/classy/templates/datetime-form.html.twig b/core/themes/classy/templates/datetime-form.html.twig
new file mode 100644
index 0000000..bf31668
--- /dev/null
+++ b/core/themes/classy/templates/datetime-form.html.twig
@@ -0,0 +1,17 @@
+{#
+/**
+ * @file
+ * Default theme implementation of a datetime form element.
+ *
+ * Available variables:
+ * - attributes: HTML attributes for the datetime form element.
+ * - content: The datelist form element to be output.
+ *
+ * @see template_preprocess_datetime_form()
+ *
+ * @ingroup themeable
+ */
+#}
+<div{{ attributes.addClass('container-inline') }}>
+  {{ content }}
+</div>
diff --git a/core/themes/classy/templates/datetime-wrapper.html.twig b/core/themes/classy/templates/datetime-wrapper.html.twig
new file mode 100644
index 0000000..45ba069
--- /dev/null
+++ b/core/themes/classy/templates/datetime-wrapper.html.twig
@@ -0,0 +1,30 @@
+{#
+/**
+ * @file
+ * Default theme implementation of a datetime form wrapper.
+ *
+ * Available variables:
+ * - content: The form element to be output, usually a datelist, or datetime.
+ * - title: The title of the form element.
+ * - title_attributes: HTML attributes for the title wrapper.
+ * - description: Description text for the form element.
+ * - required: An indicator for whether the associated form element is required.
+ *
+ * @see template_preprocess_datetime_wrapper()
+ *
+ * @ingroup themeable
+ */
+#}
+{%
+  set title_classes = [
+    'label',
+    required ? 'form-required',
+  ]
+%}
+{% if title %}
+  <h4{{ title_attributes.addClass(title_classes) }}>{{ title }}</h4>
+{% endif %}
+{{ content }}
+{% if description %}
+  <div class="description">{{ description }}</div>
+{% endif %}