LibreTorrent

3.1

LibreTorrent is a completely free torrent client based on libtorrent, and it’s built for the Android platform. Read more about LibreTorrent  

Most torrent clients available for Android devices are not free and users need to pay for the full set of features, not to mention the fact that those apps are not even open source. The LibreTorrent does the opposite, meaning the is completely free, it doesn’t have any ads, and it is open source.
 
LibreTorrent comes with support for pretty much all of the features that you would want, such as support for DHT, PeX, encryption, LSD, UPnP, NAT-PMP, and µTP, filtering based on IP, support for very large torrents, support for proxy for trackers and peers, support for Tor, the ability to move a file during the download process, and much more.
Of course, the LibreTorrent app is adapted to the needs of the Android platform, which mean that users will get access to a number of customization specifically for phones and tablet, not to mention the fact that it used material design.