Live Preview Options is a great app to add various customization fields to your Shopify products. You can add swatches, dropdown menus, buttons, text inputs, upload fields and much more. In addition, you can generate a live preview of the product as the user customizes it. Do price increases depending on the selection and even Conditional Logic to show/hide the options depending on the customer's selection. The app has no limits! As many fields as you want and as many products as you want!