Q:

Where can I find dictionaries for Opendict and Goldendict?

Asking about good offline dictionaries in Ubuntu would have created a duplicate of this question which got as answers only Goldendict and Artha.
Artha is ok but is limited to English as far as I can tell.

I would like at least some more English and French dictionaries.
I have also installed Opendict but it asks to add dictionaries. How to do it?

Many users recommend Goldendict, which comes with Wikipedia and to which I could add an English dictionary,

but for dictionary sources we are redirected to an almost dead website: most of links are dead and/or in Russian.  I cannot download any dictionaries from Babylon as they just give a link to download Babylon.exe no matter what "free-dictionary" I choose. I have extracted the exe file but no .bgl files inside (what am I missing here?). 

A:

You can use the "WordNet 3" dictionary which is supported by GoldenDict. To install it: Extract the Zip file and put it somewhere in your system then do the following:
Edit>Dictionaries>Add>Then select the extracted folder and click "Apply".
You can download WordNet 3 from this link:
http://en.sourceforge.jp/projects/sfnet_goldendict/downloads/dictionaries/WordNet3.0_1.0.zip/
Here is a collection of dictionaries:
http://www.stardict.org/download.php

