You can get more cover search scripts from
/t/1681/1 and
/c/web-sources-scripts
If you want a keyboard shortcut for a script rename the .src file and add an ampersand before your desired shortcut character:
Cover Art#Amazon.com.src
to
&Cover Art#Amazon.&com.src
Then you can press ALT+S, C, C
(ALT+S depends on your language in Mp3tag)
Cover Art_Amazon.&com.src
makes it only ALT+S, C
or with a number
&1 Cover Art_Amazon.com.src