Mininova is described as 'torrent search engine and directory on the net. It started in January 2005 as an alternative to the (at that time very popular) SuprNova, which went offline at the end of 2004 due to legal issues' and is a torrent search engine in the file sharing category. There are more than 10 alternatives to Mininova, not only websites but also apps for Windows and Tor. The best Mininova alternative is The Pirate Bay, which is free. Other great sites and apps similar to Mininova are 1337X, LimeTorrents, Torrends.to and Zooqle.
Mininova alternatives are mainly Torrent Search Engines but may also be Torrent Trackers. Filter by these if you want a narrower list of alternatives or looking for a specific functionality of Mininova.