Sold out variants
Shopify Hide sold out variants
That one thing, no merchant wants is to irritate their customers and lose them for good, just because options/variants of some products are sold out but still visible on product pages by default. The customer gets to know if the variant option is sold out or in stock only after they click on the product variant that they would like to purchase. Though this problem is relevant but there is no native solution provided by Shopify.