Below is an example for a webpage which lists different soccer balls for sale:

<script type="application/ld+json">

  {

    @context: "https://schema.org/",

    @type: "OfferCatalog",

    name: "Cakes for Sale",

    description: "A catalog of cakes offered by our online store",

    url: "https://www.example.com/all-cakes",

    numberOfItems: 2,

    itemListOrder: "https://schema.org/ItemListOrderAscending",

    itemListElement: [{

      @type: "Offer",

      itemOffered: {

        @type: "Product",

        name: "Cake1",

        image: "https://www.example.com/images/product1.jpg",

        description: "Description of cake 1",

        sku: "sku1",

        manufacturer: "Manufacturer 1",

        brand: "Brand 1",

        offers: {

          @type: "Offer",

          price: "9.99",

          priceCurrency: "USD",

          availability: "https://schema.org/InStock"

        }

      }

    }, {

      @type: "Offer",

      itemOffered: {

        @type: "Product",

        name: "Product 2",

        image: "https://www.example.com/images/product2.jpg",

        description: "Description of product 2",

        sku: "sku2",

        manufacturer: "Manufacturer 2",

        brand: "Brand 2",

        offers: {

          @type: "Offer",

          price: "199.99",

          priceCurrency: "USD",

          availability: "https://schema.org/InStock"

        }

      }

    }]

  }

</script>

once you’ve done your own code, you can check it using the schema testing sheet – https://docs.google.com/spreadsheets/d/1dDqJ9_qrTVoJOZRxieJDp9XE3Q1TCq4ixNVudVtgp2M/edit#gid=0

Here’s another example:

<script type="application/ld+json">

{

  "@context": "http://schema.org",

  "@type": "OfferCatalog",

  "name": "Competition Tennis Balls",

  "description": "High-quality competition tennis balls for professional and amateur players.",

  "url": "https://www.example.com/tennis-la/balls/competition-tennis-balls.html",

  "itemListElement": [

    {

      "@type": "Offer",

      "itemOffered": {

        "@type": "Product",

        "name": "Pro Tournament Tennis Ball",

        "image": "https://www.example.com/images/pro_tournament_tennis_ball.jpg",

        "description": "Premium quality tennis ball designed for professional tournaments.",

        "brand": "example Pro",

        "sku": "NWPRO123",

        "offers": {

          "@type": "Offer",

          "priceCurrency": "USD",

          "price": "20.00",

          "availability": "http://schema.org/InStock",

          "url": "https://www.example.com/pro-tournament-tennis-ball.html"

        }

      }

    },

    {

      "@type": "Offer",

      "itemOffered": {

        "@type": "Product",

        "name": "Championship Level Tennis Ball",

        "image": "https://www.example.com/images/championship_level_tennis_ball.jpg",

        "description": "High-performance tennis ball suitable for championship level play.",

        "brand": "Example La",

        "sku": "NWCHAMP456",

        "offers": {

          "@type": "Offer",

          "priceCurrency": "USD",

          "price": "15.00",

          "availability": "http://schema.org/InStock",

          "url": "https://www.example.com/championship-level-tennis-ball.html"

        }

      }

    }

  ]

}

</script>

Instead of Offercatalog, you may want to consider using CollectionPage schema…

Here’s an example of CollectionPage Schema for an eCommerce category page:

<script type="application/ld+json">



{



  "@context": "http://schema.org",



  "@type": "CollectionPage",



  "name": "Shopify Apps",



  "url": "https://sherpas.design/pages/shopify-apps",



  "description": "We build apps that function and feel natively Shopify",



  "image": "https://cdn.shopify.com/s/files/1/0085/8515/0560/files/logox2_500x500.png?v=1555661781",



  "isPartOf": {



    "@type": "WebSite",



    "name": "Sherpas Design",



    "url": "https://sherpas.design"



  },



  "relatedLink": [



    "https://sherpas.design/about-us",



    "https://sherpas.design/contact"



  ],



  "mainEntity": {



    "@type": "ItemList",



    "itemListElement": [



      {



        "@type": "ListItem",



        "position": 1,



        "url": "http://example.com/coffee_cake.html",



        "name": "Coffee Cake",



        "image": "http://example.com/images/coffee_cake.jpg",



        "description": "product is yummy",



        "brand": "NanesBakes"



      },



      {



        "@type": "ListItem",



        "position": 2,



        "url": "http://example.com/apple_pie.html",



        "name": "Apple Pie",



        "image": "http://example.com/images/apple_pie.jpg",



        "description": "product is yummy",



        "brand": "MumsCakesYo"



      },



      {



        "@type": "ListItem",



        "position": 3,



        "url": "http://example.com/blueberry-pie.html",



        "name": "Blueberry Pie",



        "image": "http://example.com/images/blueberry_pie.jpg",



        "description": "product is yummy",



        "brand": "NanesBakes"



      }



    ]



  }



}



</script>

More info on CollectionPage Schema for eCommerce in my other blog post here.