90% of the trackers on this list should be fully operational. Although some of theme require invites.
BestMMAtorrents - http://www.bestmmatorrents.com
BT.Davka - http://bt.davka.info
Extremebits - http://www.extremebits.org
FormulaMonkey - http://www.formulamonkey.com
FootyTorrents - http://www.footytorrents.co.uk
FullContactZone - http://www.fullcontactzone.tv
HDSporttorrents - http://www.hdsporttorrents.co.uk
MMAtorrents - http://mma-torrents.com
MMAtracker - http://mma-tracker.net
MuayThaiTorrents - http://muaythaitorrents.com
NHLtorrents - http://www.nhltorrents.co.uk
Racing-Underground - http://www.racing-underground.com
SportBit - http://www.sportbit.org
Sport-Scene - http://www.sport-scene.net
T3nnis.tv - http://t3nnis.tv
WorldBoxingVideoArchive - http://worldboxingvideoarchive.com
WWT - http://worldwrestlingtorrents.net
XWT - http://xtremewrestlingtorrents.net
XWT - Classics - http://xwt-classics.net
BoxingTorrents - http://tc-boxing.com
GrabTheInfo (MMA) - http://www.grabthe.info
http://tenyardtracker.com/login.php?returnto=/

enjoy