Some repositories have decided that current standards do not fit their metadata needs, and so have created their own requirements.
A repository-developed metadata schema for EST data in Genbank.
The Environmental Information Data Centre (EIDC) is a Natural Environment Research Council Data Centre hosted by the Centre for Ecology & Hydrology (CEH). It manages nationally-important datasets concerned with the terrestrial and freshwater sciences.
An online portal providing access to a number of NSF-supported marine geoscience projects, which has developed its own metadata requirements.