Eco-labels are one of the key tools used to implement GPP - both to develop specifications or criteria and to verify the compliance of products and services with these standards. There are many different kinds of eco-labels, for example those which address a single issue such as the Energy Star label or those which cover multiple criteria.
The Buying Green! Handbook outlines how different kinds of eco-labels can be used at each stage of the procurement process.
Here you can find a non-exhaustive list of existing EU and international eco-labels. While steps have been taken to verify this information, its accuracy cannot be guaranteed.
More information on EU Ecolabel product groups here