Online versions of some of the well-known Pons dictionaries by Ernst Klett Verlag. Basic vocabulary, economics and politics. You can define an individual search profile according to i.a. Permits translation among the 12 European languages and contains an abbreviation database.
Some entries are even available in further languages.
A large collection of mostly small dictionaries for travellers. Another example are the Esperanto dictionaries. These are quite voluminous with between 10.000 and 15.000 entries. Proposes you translations into 5 languages on the same screen. It also accepts suggestions from users for new words in all the combinations.