If you watch baseball in 2016, you're going to see some real live future Hall of Famers. You obviously can't know who just yet and won't for decades, but they will be there, from the obvious veteran superstar to the unheralded rookie just starting out. But how many? And who? That's where it gets a little complicated, because depending on how you look at it, it's arguably never been more difficult to see one live.
We have well over a century worth of data to see how many future legends are active at any given time, and dating back to 1900, there's been an average of 31 active future Hall of Famers per year. Of course, as you can see, it hasn't always been consistent, and we haven't actually seen 31 since way back in 1988:

There's three evident trends there. In 1944-45, many of the greats like Joe DiMaggio and Ted Williams missed full seasons while serving in the military, leading to a brief dip. Conversely, the period between 1925-35 is wildly over-represented, in part because of Veterans Committee shenanigans decades later. (The 1925-27 New York Giants, for example, had seven Hall of Famers, tied for the most of any non-Yankees team ever, despite finishing second, fifth and third, respectively, in the National League.)
The third, of course, is the recent mess that has prevented otherwise deserving Hall of Famers like Barry Bonds and Roger Clemens from gaining admittance due to the ongoing PED controversy, a situation that shows no signs of resolving. Between 1946-86, there was a relatively steady average of 33.6 future Hall of Famers playing each year, never falling below 27 or above 36. From 1987-97, that's fallen to 24, and while it will change when recently retired stars like Ken Griffey Jr., Derek Jeter, Chipper Jones and Mariano Rivera get in, it hasn't so far.
But there's also the fact that as the number of active Hall of Famers has declined, the number of active players has gone up. In 1960, the final year of 16-team baseball that had persisted since 1901, there were 575 active players. In 2015, as the sport has ballooned to 30 teams and relievers cycle in and out like never before, we saw 1,228 players, more than twice as many. What that means is that the percentage of Hall of Famers per season has dropped even more precipitously:

Overall, the average is 5.2 percent, but we haven't reached that since 1968. It's just 2.6 percent in the divisional play era, from 1969-2009. But even if we limit it to that period, 2.6 percent of 1,228 active players is… 31 players.
So are there 31 active Hall of Famers today? Perhaps, but it's harder than you'd think. Let's go through the candidates, in tiers. For reference, the average Hall of Famer falls between 50 WAR and 70 WAR.
Slam dunks right now, no questions asked
1. Albert Pujols (90 WAR)
2. Miguel Cabrera (63 WAR)
3. Ichiro Suzuki (57 WAR)
Pujols and Cabrera may end up as two of the top 10 right-handed hitters of all time. Despite age and injury, both had productive 2015 seasons. There's just no case to be made to have a Hall of Fame that doesn't include them. Ichiro hasn't really been an above-average player since he left Seattle, but he's likely to collect his 3,000th hit in 2016, which is all the more remarkable considering that he played nine seasons in Japan first.
The Alex Rodriguez zone
4. Alex Rodriguez (114 WAR)
Based on numbers alone, Rodriguez is one of the most elite players to ever take the field. He hit 33 homers at age 39 last season, and should be a first-ballot, inner-circle, no-doubter. Based on, well, everything else, A-Rod's induction is far from certain. Let's just leave this one here and move on.
Over-30 players with strong cases
5. Adrian Beltre (75 WAR)
6. Carlos Beltran (66 WAR)
7. CC Sabathia (60 WAR)
8. Justin Verlander (48 WAR)
9. David Ortiz (46 WAR)
10. Zack Greinke (46 WAR)
11. Robinson Cano (43 WAR)
12. Joey Votto (42 WAR)
13. Dustin Pedroia (41 WAR)
14. Yadier Molina (31 WAR)
We don't have the space here to go through each one of these players individually, other than to say, each one is going to make for very interesting arguments when their time comes. It also shows how quickly things can change, because a few years ago Chase Utley, Joe Mauer, Carl Crawford and David Wright would have been on this list, and their stars have since dimmed considerably -- you might say the same for Troy Tulowitzki and Ryan Braun. This is where you might also see consistently-good-but-rarely-great players like Matt Holliday, Mark Teixeira and Adrian Gonzalez, excellent players with very solid careers who probably are not likely to end up enshrined in Cooperstown.
Molina will fall short by most statistical standards, though there's some evidence that WAR underrates catchers, and his defensive reputation and position as backstop leader of two title-winning teams could be enough, depending on how the remainder of his career goes.
30 and under players on the right track
15. Felix Hernandez (47 WAR)
16. Clayton Kershaw (47 WAR)
17. Evan Longoria (43 WAR)
18. Andrew McCutchen (40 WAR)
19. Mike Trout (39 WAR)
20. David Price (32 WAR)
21. Buster Posey (29 WAR)
22. Jason Heyward (28 WAR)
23. Giancarlo Stanton (25 WAR)
24. Chris Sale (23 WAR)
25. Madison Bumgarner (23 WAR)
26. Paul Goldschmidt (22 WAR)
27. Bryce Harper (19 WAR)
28. Manny Machado (17 WAR)
29. Craig Kimbrel (13 WAR)
30. Aroldis Chapman (11 WAR)
Hernandez is somehow still not even 30, though he's coming off the worst year of his career. You could make a very strong argument that if not for the "must play 10 seasons" requirement, Trout could retire right now and be inducted, thanks to the historically great start to his career. You might be able to do the same for Kershaw, who already owns three NL Cy Young Awards and an NL MVP Award, and Harper just had one of the most historic seasons ever. Goldschmidt is basically Jeff Bagwell, who deserves to be in and may be as soon as this year. 
Everyone else here is on the right path, though it's a virtual guarantee one or more won't make it. You could also argue for Matt Harvey here, despite just one full season. Kimbrel and Chapman won't do well by WAR, though that's not how closers get into the Hall of Fame. They're unquestionably two of the most elite relievers of all time; they just need to continue to prove they can do it for several more years.
So that's 30 possibles right there, but then…
The "two years or less" young field
Mookie Betts / Noah Syndergaard / Jacob deGrom / Corey Seager / Carlos Correa / Francisco Lindor / Kyle Schwarber / Kris Bryant / Miguel Sano / Joc Pederson / Byron Buxton / Michael Conforto / Xander Bogaerts / etc.
2015's rookie class was arguably the best in a century, and looking at the names above (including as well some second-year players), it's easy to see why. Baseball saw a simply stunning influx of talent reach the big leagues over the past 18 months, and while it's far too soon to know how these careers are going to play out, it's hard to imagine that at least one or two of these elite young players won't reach immortality some day.
Also, don't forget that we're talking about Hall of Famers in 2016, so include the next wave of prospects who are likely to show up next year, even if only briefly -- guys like Julio Urias, J.P. Crawford, Lucas Giolito and so on -- and therefore are eligible for this experiment.
Ultimately, however, we've mentioned far more than 31 names. Barring a total change in the way the Hall of Fame electorate does business, only a fraction of these will make it in. Even though baseball's talent is probably the best it's ever been, the induction process into Cooperstown hasn't really reflected that.