For finding ftp sites you can use this trick. This is simple trick using google search engine. If you know google searching tactics,then you can whatever faster.
How to Use index of for ftp?
Search in google as
index of ftp/ +file_extension
replace the file_extension with file extension which you want to search. (avi,mp3,aac,pdf…etc)
For Eg:
if you want to search for pdf ,then search as:
index of ftp/ pdf
if you want to search for avi files,then search as:
index of ftp/ avi
How to Use index of for ftp?
Search in google as
index of ftp/ +file_extension
replace the file_extension with file extension which you want to search. (avi,mp3,aac,pdf…etc)
For Eg:
if you want to search for pdf ,then search as:
index of ftp/ pdf
if you want to search for avi files,then search as:
index of ftp/ avi