WooCommerce Cart Add-ons plugin allows you to add additional options to your cart such as gift wrapping, donation, and upsells. Some of the key features of the plugin include:

• Ability to add custom fields to the cart page, such as checkboxes, text fields, and select menus.
• Option to add a fee or discount to the cart total based on the options selected by the customer.
• Ability to create upsells, offering customers the chance to add related or complementary products to their order.
• Ability to add donation options to the cart, allowing customers to make a charitable contribution as part of their purchase.
• Ability to set conditions for when the custom fields should be displayed, such as only showing certain fields for specific products or categories.
• Ability to customize the labels and messages displayed on the cart page.

These are some of the notable features of the WooCommerce Cart Add-ons plugin, it is always recommended to check the official website or documentation of the plugin to see the full list of features.