I have been working on a project to create a searchable file containing active links for data sources. I have compiled a basic Google Spreadsheet which I share online for anyone interested. The data sources included cover a wide range of statistical themes. It has been quite effective in my work as I find it especially hard to navigate across multiple databases and memorise the location of variables of interest. Apparently, the entries are primarily influenced by my knowledge and personal research interests.
You are welcome to access/share the document online and download it for personal use.
I urge users to leave comments if any errors, invalid links e.t.c. are detected.
Please, let me know if you wish to be granted with editing rights in order to add sources.