Display whatever you want in an entities card row.

For installation instructions see this guide.

Install template-entity-row.js as a module.

resources:
  - url: /local/template-entity-row.js
    type: module

Note: This is not a card. It's a row for an entities.

type: entities
title: Default
entities:
  - light.bed_light
  - entity: input_boolean.car_home
  - type: custom:template-entity-row
    icon: mdi:lamp
    name: "The light is {{states('light.bed_light')}} but nobody's"
    state: "{% if is_state('input_boolean.car_home', 'on')%} home {% else %} away {% endif %}"
    secondary: "It's {{states('sensor.time')}}"
    active: "{{ is_state('light.bed_light', 'off') }}"
  - type: custom:template-entity-row
    icon: mdi:car
    name: Hi there
    condition: "{{is_state('input_boolean.car_home', 'on')}}"

• icon, name, state, secondary, image selects what icon, name, state, secondary_info text and entity_picture to display respectively.
• active if this evaluates to "true" or "false", the icon gets will always look active or inactive respectively.
• entity if this evaluates to an entity id, icon, name, state and image will be taken from that entity unless manually overridden. Specifying an entity will also let you use action.
• condition if this is set but does not evaluate to "true", the row is not displayed.
• toggle if this evaluates to "true" a toggle is shown instead of the state. The toggle is connected to the entity. This will only show a toggle, nothing else. No sliders, no dropdowns, no media controls. toggle means Toggle.
• tap_action, hold_action, double_tap_action: see below.
• color the CSS color of the icon.

All options accept jinja2 templates.

Jinja templates have access to a few special variables. Those are:

• config - an object containing the card configuration
• user - the username of the currently logged in user
• browser - the deviceID of the current browser (see browser_mod).
• hash - the hash part of the current URL.

In evaluated templates the function _(<key>) (underscore) will localize the <key> to the current language. E.g. _(state.binary_sensor.motion.off) will be replaced with Clear if your language is set to English.

To find the available keys, open your browsers console, type in the following and press Enter:

document.querySelector("home-assistant").hass.resources;

Context variables are supported as well, for instance: _(ui.duration.second, count, 30) (note there are no quotes around count).

tap_action, hold_action and double_tap_action can be templated if the template evaluates to a valid action configuration in python format. Standard YAML without templates works too.

Eg:

type: custom:template-entity-row
entity: light.bed_light
# Standard yaml configuration - No templates allowed
hold_action:
  action: more-info
# JSON return format
tap_action: |
  {
    "action": "toggle",
    "confirmation": {
      "text": "Do you really want to turn {{ state_attr(config.entity, 'friendly_name') }} {% if is_state(config.entity, 'on') %}off{% else %}on{% endif %}?",
    },
  }
double_tap_action:
  action: toggle

Because you're not using it correctly. This is not a card. It's an entity row, and is meant to be used inside the entities card

Because "toggle" means a toggle. It's the simplest possible way to control an entity, and anything beyond that is not in the scope of this row and will not be added.

This may happen if you use the GUI editor to edit a template based value. Since Home Assistant redraws the row every time you make any change to the configuration in the GUI editor, it will try to render the template every time you push a key. Since the template will be invalid for most of the time while you're editing it, you will get a lot of errors.
There's unfortunately nothing I can easily do about this behavior.