H33T is a major torrent tracker and indexer with unconventional design. It has a very user friendly layout with all torrents categorized into different categories represented by funky icons. They also provide user registration to save favourites, lists top contributors and a forum which has all the help you need. Last year owing to court orders their domain has been seized and dns name servers are wiped out, for which they moved to a new domain. Recently again they have been blocked by major service providers in UK due to court orders along with kickass torrents and fenopy. Over all it has around 1.5 million torrents and good place to find your weekend fix. Their search is quite powerful allowing you to search in 15 different categories.
BitSnoop is one of the most famous torrent sites with around 24 million torrents indexed from 370 websites totalling to 29PB of files. Needless to say, they are the largest of the torrent indexers. Around 1.2million verified torrents are listed on their website. They even provide an api to track torrents and scan torrents and take daily torrents dump. They are blocked in UK due to court orders citing copyright infringement. The interface is clean with a single search bar like any other torrent search engines and categories to search in. They also accept donations on bitcoin and they provide advanced search facility through which you can search for almost any torrent on the website with size, category and name filters. There is a search engine plugin for firefox also. The list of features they provide large, like magnetized links, your bt history on their site, tvfinder etc,
Update May 2017: Bitsnoop has been shutdown
emp3world.com is unique service where visitors edit the site content. When the automated algorithm detect growing interest in some songs, the system immediately search the web for this mp3 files and add them to database. In similar way they replace all broken links with new ones. Discover newest and best music hits, that music fans around the world listen here. emp3world.com is in compliance with copyrights. They have a very simple web interface with a big search bar and listing of Top downloads, current trends and latest downloads added. All search results are presented with an option to play, download and embed them on you website along with downloading the entire album. This site is blocked in UK according to court orders citing copyright infringement.