<?php
defined( 'ABSPATH' ) || exit;
get_header( 'shop' );
do_action( 'woocommerce_before_main_content' );
?>
<header class="woocommerce-products-header">
    <?php if ( apply_filters( 'woocommerce_show_page_title', true ) ) : ?>
        <h1 class="woocommerce-products-header__title page-title"><?php woocommerce_page_title(); ?></h1>
    <?php endif; ?>

    <?php
    do_action( 'woocommerce_archive_description' );
    ?>
</header>
<?php
$args = array(
    'post_type'      => 'product',
    'posts_per_page' => 8,
    'meta_query'     => array(
        'relation' => 'OR',
        array( // Simple products type
            'key'           => '_sale_price',
            'value'         => 0,
            'compare'       => '>',
            'type'          => 'numeric'
        ),
        array( // Variable products type
            'key'           => '_min_variation_sale_price',
            'value'         => 0,
            'compare'       => '>',
            'type'          => 'numeric'
        )
    )
);

 $loop = new WP_Query( $args );
    if ( $loop->have_posts() ) {
        while ( $loop->have_posts() ) : $loop->the_post();
            do_action( 'woocommerce_shop_loop' );
            wc_get_template_part( 'content', 'product' );
        endwhile;
    } else {
         woocommerce_get_template( 'loop/no-products-found.php' );
    }
    
do_action( 'woocommerce_after_main_content' );
do_action( 'woocommerce_sidebar' );
get_footer( 'shop' )

参考：https://www.godaddy.com/garage/get-a-list-of-woocommerce-sale-products/