Magento – Magento2: Cross-sell not showing in cart, missing crosssell.phtml file

Install below extension that will help you to create extra page after cart

https://github.com/tmhub/suggestpage

above extension add extra page after cart and that page you will add these code and you will get cross-sell product data

change your indexController indexAction as below

public function indexAction()
{
    $this->loadLayout()
        ->_initLayoutMessages('checkout/session')
        ->_initLayoutMessages('catalog/session');

    $_product = Mage::getModel('catalog/product')->load(1); //here 1 is product Id
    $block =  $this->getLayout()->createBlock('checkout/cart_crosssell')->setProduct($_product)->setTemplate('checkout/cart/crosssell.phtml');
    $this->getLayout()->getBlock('content')->append($block);

    $this->renderLayout();
}

and for your 4 product issue please check in your app/design/frontend/YourPackge/YourTheme/checkout/cart/crosssell.phtml file any condition who breaks for loop after four product then change it.

to increase limit for cross-sell product follow this quick step

1) copy app/code/core/Mage/Checkout/Block/Cart/Crosssell.php file to app/code/local/Mage/Checkout/Block/Cart/Crosssell.php

2) find this line and increase limit as per your need protected $_maxItemCount = 4;

If you want to call a block in html file, AJAX loading the content is the way to it. Magento 2's export functionality does the same thing. When you change export entity magento has to change filter html that is rendered. so magento calls this Controller

Magento\ImportExport\Controller\Adminhtml\Export\GetFilter

Observe the code in execute method. There are two key things

 $resultLayout = $this->resultFactory->create(ResultFactory::TYPE_LAYOUT);
return $resultLayout;

So you are going to return a layout and NOT a page layout.

Name of your xml will be .xml That means you will create a xml like this

<layout xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:View/Layout/etc/layout_generic.xsd">
<container name="root" label="Root">
           <block class="Magento\Checkout\Block\Cart\Crosssell" name="checkout.cart.crosssell" template="Magento_Catalog::product/list/items.phtml" after="-">
                <arguments>
                    <argument name="type" xsi:type="string">crosssell</argument>
                </arguments>
                <block class="Magento\Catalog\Block\Product\ProductList\Item\Container" name="crosssell.product.addto" as="addto">
                    <block class="Magento\Catalog\Block\Product\ProductList\Item\AddTo\Compare"
                           name="crosssell.product.addto.compare" as="compare"
                           template="Magento_Catalog::product/list/addto/compare.phtml"/>
                </block>
            </block>
</container>

Notice that parent node is and not That's it. You will have your cross sell html as response to your ajax request. Just insert the html wherever you want.

To an ajax call you can write jquery inside your html. somthing like this

<script>
require(['jquery'],function($){
   $.get('url/of/controller',function(response){
      //do stuff with your html
   })
})
<script>

If you knockout do with knockout. Or doing it with x-magento-init is even better.

Just start with a simple echo "Hello world" in your controller and it will become clear. If your controller action is route/controller/action then your layout name should be route_controller_action.xml . That's why result factory knows which layout.xml to use from your module