Where are the field variables in a block template?
They're in the content variable, e.g.

&lt;div{{ attributes }}&gt;
  {{ title_prefix }}
  {% if label %}
    &lt;h2{{ title_attributes }}&gt;{{ label }}&lt;/h2&gt;
  {% endif %}
  {{ title_suffix }}
  {% block content %}
    {{ content.field_foo }}
    {{ content|without('field_bar') }}
    {{ content.field_bar }}
  {% endblock %}
&lt;/div&gt;


For reference, these are the default core variables you have available (from the core template:


  
  plugin_id: The ID of the block implementation.
  label: The configured label of the block if visible.
  configuration: A list of the block's configuration values.
  label: The configured label for the block.
  label_display: The display settings for the label.
  provider: The module or other provider that provided this block plugin.
  Block plugin specific settings will also be stored here.
  content: The content of this block.
  attributes: array of HTML attributes populated by modules, intended to be added to the main container tag of this template.
  id: A valid HTML ID and guaranteed unique.
  title_attributes: Same as attributes, except applied to the main title tag that appears in the template.
  title_prefix: Additional output populated by modules, intended to be displayed in front of the main title tag that appears in the template.
  title_suffix: Additional output populated by modules, intended to be displayed after the main title tag that appears in the template.