Then i gave a try to write one. this typical bookmarklet firstly ask for few predefined options then extract all the link of matching types. And options are optimized for google filetype : *** search result.
To use copy following lines and then create a bookmark with this text in url.
How to use:
Firstly search in google using filetype: option (say filetype:pdf binary heap)
the click this bookmark.
will see a prompt, choose a number or type the filetype or left empty to list all.
another window will open, with the list of links. copy it or save it in plain text format use wget or any download manager you like, grab the files.
NB: this is my first bookmarklet, could face error, let me know. And have some idea to develop it.