Block.php

<?php

    namespace YourPlugin\Blocks;

    abstract class Block{

        /**
         * Block title
         *
         * @var string
         */
        protected $title = '';

        /**
         * Properties for this block
         *
         * @var array
         */
        protected $properties = [];

        /**
         * Constructor;
         */
        public function __construct( $props = [])
        {
            $this->properties = wp_parse_args( $props, $this->get_defaults() );
        }

        /**
         * Register this block:
         *
         * @return void
         */
        public function register()
        {
            
            add_action( 'acf/init', function(){

                if( function_exists( 'acf_register_block_type' ) ){
                    acf_register_block_type([
                        'name'              =>      $this->get_slug(),
                        'title'             =>      $this->title,
                        'description'       =>      $this->prop( 'description' ),
                        'render_template'   =>      $this->get_template(), 
                        'category'          =>      $this->prop( 'category' ),
                        'icon'              =>      $this->prop( 'icon' ),
                        'keywords'          =>      $this->prop( 'keywords' )
                    ]);
                }
            });

            if( function_exists( 'acf_add_local_field_group' ) ){
                acf_add_local_field_group([
                    'key' => 'block_fields_'.$this->get_slug(),
                    'title' => $this->title,
                    'fields' => $this->get_sanitized_fields(),
                    'location' => [[[
                        'param' => 'block',
                        'operator' => '==',
                        'value' => 'acf/'.$this->get_slug()
                    ]]],
                    'menu_order' => 0,
                    'position' => 'normal',
                    'style' => 'default',
                    'label_placement' => 'top',
                    'instruction_placement' => 'label',
                    'hide_on_screen' => '',
                    'active' => true,
                    'description' => '',
                ]);
            }
        }
        
        
        /**
         * Return the fields
         *
         * @return array
         */
        public function get_fields()
        {
            return [];
        }
    
        /**
         * Get all fields and add defaults to them
         * 
         * @return array
         */
        public function get_sanitized_fields( $fields = null )
        {
            if( is_null( $fields ) ){
                $fields = $this->get_fields();
            }

            foreach( $fields as $key => $field ){
                if( !isset( $field['key'] ) ){
                    $fields[$key]['key'] = $field['name'];
                }

                if( isset( $field['sub_fields'] ) && !empty( $field['sub_fields'] ) ){
                    $fields[$key]['sub_fields'] = $this->get_sanitized_fields( $field['sub_fields'] );
                }
            }
            
            return $fields;
        }


        /**
         * Return a property
         *
         * @return mixed
         */
        public function prop( $key, $default = null )
        {
            if( isset( $this->properties[ $key ] ) ){
                return $this->properties[ $key ];
            }

            return $default;
        }
            

        /**
         * Return the slug for this block
         *
         * @return string
         */
        public function get_slug()
        {
            return sanitize_title( $this->title );
        }


        /**
         * Return the template for this block:
         *
         * @return string
         */
        public function get_template()
        {
            return 'blocks/'.$this->get_slug().'.php';
        }


        /**
         * Return default properties
         *
         * @return array
         */
        public function get_defaults()
        {
            $defaults = [
                'description' => '',
                'category' => 'common',
                'icon' => 'admin-comments',
                'keywords' => []
            ];

            return apply_filters( 'my_plugin_custom_block_defaults', $defaults, $this );
        }
    }

example.php

<div class="example-block">
    <h3><?php echo get_field( 'example' );?></h3>

    <?php if( get_field('button') && is_array( get_field( 'button' ) ) ):
            $button = get_field( 'button' );    
    ?> 
        <a href="<?php echo esc_attr( $button['link'] );?>" class="button primary">
            <?php echo esc_html( $link['title'] );?>
        </a>
    <?php endif;?>
</div>

ExampleBlock.php

<?php

    namespace YourPlugin\Blocks;

    class ExampleBlock extends Block{

        /**
         * Title of this block
         * Determens how this block is added, saved and which template to use.
         * 
         * Block name: "Example"
         * Block slug/id: example
         * Template: /blocks/example.php
         *
         * @var string
         */
        protected $title = 'Example';


        /**
         * Return the fields
         *
         * @return Array
         */
        public function get_fields()
        {
            return [
                [
                    'label' => 'An example field',
                    'name' => 'example',    //field name for get_field()
                    'type' => 'text'        //type of field to show
                ],
                [
                    'label' => 'Button',
                    'name' => 'button',
                    'type' => 'link'
                ]
            ];
        }

    }

All blocks that you create (like ExampleBlock above) should be registered in a php-file:

( new ExampleBlock() )->register();

And by adding a get_defaults() function to your new blocks, you can control some of its settings:

  /**
    * Return default properties
    *
    * @return array
    */
    public function get_defaults()
    {
        return [
            'description' => 'This is a custom block description',
            'category' => 'common',
            'icon' => 'yes',
            'keywords' => [ 'myblock', 'testing' ]
        ];
    }