There are a host of other certifications, issued by a variety of international bodies, with Fairtrade being one of the most well-known.
Many of these certifications are sector or issue specific, and some have legal status in particular countries. Some can be quite burdensome in cost and regulation, but then you must evaluate the potential advantage in securing your supply chain and exploiting the marketing benefit.
A comprehensive list is available at Ecolabels.
A more recent innovation is the green labelling initiative started by influential retailer Amazon. A quick examination of the availability of products might be informative. Some products from well known brands do not appear to be particularly green yet have some sort of certification. Some products from opportunist suppliers sell apparently standard green goods at premium prices, presumably supported by the green credentials. There are also large numbers of apparently green goods, which are competitively priced, which do not have any formal green certification. The message here is to carefully consider which label systems might prove helpful, and do not miss the opportunity to market your products or services effectively.