Alexa sites for "File sharing":
http://www.alexa.com/topsites/category/Top/Computers/Internet/File_Sharing
Alexa sites for Torrents:
http://www.alexa.com/topsites/category/Top/Computers/Internet/File_Sharing/BitTorrent
Torrent Meta Search Engines:
https://torrentz.eu/ List of torrent websites that Torrentz.eu searches: https://torrentz.eu/help (go to bottom of the page)
Torrent Blogs and other
Torrent Freak: https://torrentfreak.com/