There are my modules of CMS Bitrix (version up to 15) for internet shops. They're not supported already!
Allow to add items to the cart by article or some other properties.
Convenient shopping cart.
The battle of brands, allows you to arrange a competition between any elements.
The battle of discounts.
Module of joint purchases for online stores. Unfortunately it was not finished.
The module is set the limit for the minimum of cart amount and of quantity of the order.
Automatic posting of photos (goods and galleries) to albums of social networks.
Automatic publication of goods in social networks (facebook.com and vk.com).
Export of goods to YML for Yandex.Market