Some of the names on this list are bigger than others, but there's a common denominator: when these players perform well, their teams are incredibly tough to beat.
Here are seven X-factors who will play a big role down the stretch.
Cam Reddish, Duke
If Reddish hits 3s at a high rate in March, Duke will probably win the national championship. That may sound too simple, but it makes sense when you think about it.
Zion Williamson is amazing for a multitude of reasons, but what's underrated about him is his consistency. The guy rarely, if ever, has a bad game. R.J. Barrett has thrown up a few clunkers, but for the most part, he's been phenomenal. Tre Jones is steady at the point, and Duke has some other nice complementary pieces in Jack White and Marques Bolden.
Reddish is the guy who has the most variance on Duke. He's only shooting 35.9 percent from the floor, but at his best, he's exactly what the Blue Devils need: an ace defender who can spread the floor for Williamson and Barrett while attacking closeouts.
When Reddish is on, Duke blows people out. He's hit a combined eight 3s in his last two games, and the Blue Devils have won those bouts by an average of 27.5 points. Reddish went 1-for-11 against Georgia Tech, and Duke still won, but was trailing for a portion of the second half.
Duke is really good with or without a hot Reddish. But when he's going, the Blue Devils are unbeatable.
Brad Davison, Wisconsin
Playing with Ethan Happ is an outside shooter's dream. Not only does he draw double-teams constantly, but he's a skilled enough passer to find the open man. That's an ideal environment for a spot-up guy.
Wisconsin is playing some of its best ball of the year, and its performance has taken off with Davison's. The sophomore guard has made multiple 3s and scored double-digit points in his last four games, all Badger wins. He's always been a good defender; Davison is the guy who makes broadcasters spit cliches like "grit" several times per game. It may be overdone, but there's truth in it. Davison is always taking charges and diving on the floor for loose balls.
That's all great, and valuable to what Wisconsin does. But when he's draining open 3s, the Badgers reach another level. Davison is up to 44.3 percent from long range, and if he keeps that mark above 40, Wisconsin should go deep in the tournament.
And a side note: If Davison keeps up this hot shooting, opponents may have to think twice about doubling Happ. That's a pick-your-poison scenario that the Badgers welcome.
De'Andre Hunter, Virginia
Hunter may be too good of a player to be considered an X-factor, but given the context of last year's NCAA tournament, he is. Hunter missed the UMBC game. Who knows what would have happened if he played?
He was Virginia's most talented player last season, but not necessarily its best. Hunter is both this year. And he's so important to the Cavaliers because nobody else on the roster does what he does.
Hunter is a bully of a defender who can get isolation buckets in a pinch, and his shooting has progressed. Virginia fell just short against Duke a few weeks ago, but it was close because of Hunter's shot creation. He was the one guy the Cavaliers had who could go toe-to-toe with Duke's star-studded freshmen.
Hunter plays within Virginia's system, but he's also the type of guy who would thrive in any system. And if the Cavaliers find themselves struggling in the NCAA tournament, Hunter presents a Plan B they didn't have a year ago. If Virginia is going to make a tournament run, Hunter will have plenty to do with it.
Theo John, Marquette
John is the biggest reason Marquette's defense has improved so much. It's gone from 'dreadful' last season to 'competent' this year, and John is one of the most feared rim-protectors in the Big East.
John is averaging 4.4 blocks per 40 minutes, and the Marquette defense is much better when he's on the floor. The Golden Eagles have a defensive rating of 91.3 when John is in the game, per Sports Reference. Their team mark is 94.9, and John has the best individual clip among Marquette regulars. The defense falters when he's on the pine.
We know Markus Howard is going to score a ton of points. But Marquette isn't a serious threat if the defense is what it was in 2017-18, regardless of Howard's excellence. John is the Golden Eagles' best, and most important, defensive piece.
Jordan Bowden, Tennessee
Tennessee's two best players, Grant Williams and Admiral Schofield, are a bit redundant. That's not a bad thing. In fact, it's ideal. When one is on the bench, the other is able to keep lineups afloat, and vice versa.
Bowden provides a different element. The Tennessee offense, ranked second, just runs more smoothly when he's in the game. Bowden's offensive rating is second on the team after Williams (and ahead of Schofield, surprisingly).
He's Tennessee's most reliable outside shooter after Schofield; Bowden is shooting 36.8 percent from 3-point range and is able to guard multiple guys on the other end. One of Bowden or Jordan Bone needs to play extremely well in the NCAA tournament in order for Tennessee to win it all. Bowden has been more consistent this season. If he can approach 40 percent from 3-point land, good luck beating the Volunteers.
Devon Dotson, Kansas
Kansas will need to reinvent itself in order to become a serious player in March due to Udoka Azubuike's injury. For better or worse, the Jayhawks will need to shoot the heck out of the ball and beat teams from the perimeter. Dotson has been solid this season, but he'll have to jump a level in order for Kansas to go on a run.
His numbers are good. Dotson is averaging 11.2 points and 3.5 assists while shooting 48.3 percent form the floor and 41.3 percent from 3. But he's only jacking two 3s per game. Kansas is thin on the interior outside of Dedric Lawson, so that number will need to rise. Dotson is Kansas' most dynamic playmaker but he often defers to Lawson and Lagerald Vick. It's easy to see why. Those guys are veterans, and they're really good.
But Dotson has a combination of speed and ball-handling that those guys don't. He's a freshman. Increased usage may actually prove to be detrimental to Kansas' win total. But an assertive Dotson is the Jayhawks' best shot to defend their Big 12 title.
Look to see if he's more aggressive the rest of February.
Ryan Cline, Purdue
Purdue is third in the country in offense, and frankly, that number doesn't make sense at first glance outside of acknowledging Carsen Edwards' dominance. But it illustrates just how good Cline has been as a second option.
Cline isn't your prototypical second guy. He doesn't really create his own offense. But he's such a lethal shooter than he makes up for it. Cline is canning 44.2 percent of his 3s on a hefty 7.5 attempts per game, and they are not easy attempts. When Cline gets an open spot-up 3, it's automatic. But he usually has to work hard to whip around screens to find open looks since defenses pay such close attention to him.
No Boilermaker outside of Edwards or Cline averages double digit scoring. The question: once Purdue faces tougher defenses deeper in the Big Ten and NCAA tournament, will Cline be able to shake free for those 3-point looks? He'll need to, because Edwards can't do it all by himself. Cline has been awesome, but he's limited. It's a little concerning that Purdue lacks a reliable shot creator after Edwards.
Matt Painter also deserves credit for freeing up Cline. If he continues to shoot 44 percent from 3, the Boilermakers will go far. But it remains to be seen how sustainable that is.