WooCommerce Chained Products Extension :
Chained Products is a good alternative to product bundles and composite product extension if you are looking for simple yet powerful solution for selling multiple products in combination. After installation you can create combo product from any combination of simple or downloadable products. You also can chain as many products a you want.
You can give special discount if they purchase combo rather than single products and this will enhance your selling volume. After installation, you can easily add new chained product as usual like creating simple products and latter on chain other products to them as needed or preferred.