Use entire file for the contents of page.list-collections.liquid. This specific version of the file was created to work with the premium Shopify theme District. Follow the guide at https://help.shopify.com/themes/customization/collections/featuring-collections-using-link-lists

page.list-collections.liquid

<!-- /templates/page.liquid -->
<section class="page page-top">
  <div class="wrapper">
    <header class="content-util">
    {% include 'breadcrumb' %}
    {% include 'social-icons' %}
    </header>
    <header class="page-header">
      <h1>{{ page.title }}</h1>
    </header>
  </div>
</section>

<section class="page">
  <div class="wrapper">
    <div class="content-container narrow rte">
      {{ page.content }}
    </div>
    <div class="featured-grid content-container rte">
      {% comment %}
        Collections are listed here.
      {% endcomment %}

      {% capture uses_minimal_framework %}{% include 'product-loop' %}{% endcapture %}

      {% if uses_minimal_framework contains 'Liquid error' %}
        {% assign uses_minimal_framework = false %}
        {% assign grid_item_width = 'large--one-quarter medium--one-third small--one-half large--col-3 medium--col-4 small--col-6' %}
      {% else %}
        {% assign uses_minimal_framework = true %}
        {% assign grid_item_width = 'span3' %}
      {% endif %}

      {% assign image_size = '720x' %}

      {% if linklists[page.handle].links.size > 0 %}

        {% assign number_of_links = 0 %}

        <div class="row row-3 grid-uniform{% if uses_minimal_framework %} row{% endif %} clearfix">

          {% for link in linklists[page.handle].links %}

            {% if link.type == 'collection_link' %}

              {% comment %}
              If we have a collection link.
              {% endcomment %}   

              {% assign collection = link.object %}
              {% assign number_of_links = number_of_links | plus: 1 %}

              <div class="box grid__item grid-item product-grid-item {{ grid_item_width }} text-center">
                <div class="grid__image product-grid-image">
                  <a href="{{ link.url }}" class="grid-image--centered">
                  {% comment %}
                    Bring in the featured image of the first product in the collection if no collection
                    image has been uploaded for it.
                  {% endcomment %}
                  {% if collection.image %}
                    <img src="{{ collection | img_url: image_size }}" alt="{{ link.title | escape }}">
                  {% else %}
                    {% assign product = collection.products.first %}
                    <img src="{{ product | img_url: image_size }}" alt="{{ link.title | escape }}">
                  {% endif %}
                  </a>
                </div>
                <figcaption class="below">
                  <h3><a href="{{ link.url }}" class="collection-item__title">{{ link.title }}</a></h3>
                </figcaption>
              </div>

              {% if uses_minimal_framework %}
                {% cycle 'clear-item': '', '', '', '<div style="clear:both"></div>' %}
              {% endif %}

            {% elsif link.type == 'page_link' %}

              {% comment %}
              If we have a page link.
              {% endcomment %}

              {% assign number_of_links = number_of_links | plus: 1 %}

              {% assign linked_page = link.object %}                    
              {% assign have_image = false %}

              {% comment %}
                Does the page contain an image? If so, let's use it.
              {% endcomment %}

              {% if linked_page.content contains '<img' %}

                {% assign have_image = true %}
                {% assign src = linked_page.content | split: 'src="' %}
                {% assign src = src[1] | split: '"' | first %}
                {% capture image_suffix %}_{{ image_size }}.{% endcapture %}
                {% assign src = src | replace: '_small.', image_suffix | replace: '_compact.', image_suffix | replace: '_medium.', image_suffix | replace: '_large.', image_suffix | replace: '_grande.', image_suffix %}

              {% comment %}
                If the page contains no image, and that page features collections, let's grab the image of the first
                collection on it.
              {% endcomment %}

              {% elsif linklists[linked_page.handle].links.size > 0 and linklists[linked_page.handle].links.first.type == 'collection_link' %}

                {% assign have_image = true %}
                {% assign collection = linklists[linked_page.handle].links.first.object %}

                {% if collection.image %}
                  {% assign src = collection | img_url: image_size %}
                {% else %}
                  {% assign src = collection.products.first | img_url: image_size %}
                {% endif %}

              {% endif %}

              <div class="box grid__item grid-item product-grid-item {{ grid_item_width }} text-center">
                <div class="grid-image product-grid-image">
                  <a href="{{ link.url }}" class="grid-image--centered">
                    {% if have_image %}
                      <img src="{{ src }}" alt="{{ link.title | escape }}" />
                    {% else %}
                      <img src="{{ link.title | handle | append: '_' | append: image_size | append: '.png' | file_url }}" alt="{{ link.title | escape }}" />
                    {% endif %}
                  </a>
                </div>
                <figcaption class="below">
                  <h3><a href="{{ link.url }}" class="collection-item__title">{{ link.title }}</a></h3>
                </figcaption>
              </div>

              {% if uses_minimal_framework %}
                {% cycle 'clear-item': '', '', '', '<div style="clear:both"></div>' %}
              {% endif %}

            {% endif %}

          {% endfor %}

        </div>

        {% if number_of_links == 0 %}

        <div class="grid">
          <div class="grid__item grid-item rte text-center">
            <p>
              There are no links of type <i>Collection</i> in your <b>{{ page.title }}</b> link list.
              Go ahead and <a href="/admin/link_lists/{{ linklists[page.handle].id }}" target="_blank">edit your link list</a> to use links that point to collections.
            </p>
          </div>
        </div>

        {% endif %}

      {% else %}

      <div class="grid">
        <div class="grid__item grid-item rte text-center">
          <p>
            You do not have a link list with a handle set to <kbd>{{ page.handle }}</kbd>, or you do and it's empty. 
            Go ahead and create a link list called <b>{{ page.title }}</b> on your <a href="/admin/links" target="_blank">Navigation page</a> and populate that link list with links that point to collections, to see collections listed here.
            Make sure the link list also has a handle set to <kbd>{{ page.handle }}</kbd>.
          </p>
        </div>
      </div>

      {% endif %}

      <style>
        kbd { 
          background-color: #FBFBE4;
          padding: 1px 4px;
          border-radius: 3px;
        }
      </style>
    </div>
  </div>
</section>