Hall of Fame quarterbacks become free agents about as often as the NFL loses a television ratings battle.

Almost never.

So, for the three active leaders in career passing touchdowns and yardage — all ranking in the top-six all-time — to be free agents at the same time is unprecedented.

NFL free agency and the Draft should be more exciting than ever because of the quarterbacks, and Tom Brady is the domino holding up every needy team’s plans. Here is The Post’s prediction of where the chips will fall in 2020:

Tom Brady: Chargers

Is it all a bluff that Brady will split with the Patriots? He seems to be loving the extra attention. And where do people who love attention wind up living? Los Angeles or Las Vegas. Don’t underestimate the drive to prove he can win without sharing credit with Bill Belichick – or even a mega personality like Jon Gruden. The Chargers are among the most talented of the new teams tied to Brady. Even Patriots owner Robert Kraft might not be able to save this marriage.

Philip Rivers: Colts

After Andrew Luck’s surprise retirement, Jacoby Brissett played well enough to take the Colts out of the running for a top draft pick but not well enough to win the job long term. Rivers is looking for a win-now situation (three years maximum), and the Colts offer one of the NFL’s best offensive lines. He would be reunited with coach Frank Reich (2013-15, Chargers assistant). Unless he retires.

nfl free agency qbs philip rivers drew brees tom brady
Philip Rivers, Drew Brees, Tom BradyGetty Images (3)

Drew Brees: Saints

Brees hasn’t re-signed yet, but he made it clear he is returning for a 20th season and only to play for the Saints.

Dak Prescott: Cowboys

Nothing would re-villainize “America’s Team” like signing Brady. But the smart bet here is on franchise or transition tagging and working out a long-term extension with Prescott, while hoping a coaching change is what elevates this talented roster. The Cowboys wasted the gift of an undrafted Tony Romo and four years of Prescott as a low-paid fourth-round pick.

Teddy Bridgewater: Buccaneers

The market’s expected willingness to spend on Bridgewater is surprising considering he has made six starts in the last four years. The former first-round pick is past the dislocated knee that nearly ended his career in 2016, but he still hasn’t thrown for more than 14 touchdowns in a season. History will change playing for coach Bruce Arians.

Ryan Tannehill: Titans

Another team in the Brady sweepstakes. The Titans must decide whether to put a tag on Tannehill by March 12, six days before Brady can sign. Let’s take an educated guess that Brady’s friend, Titans coach Mike Vrabel, will be tipped off to whether Brady wants to come or not so proper arrangements can be made.

Marcus Mariota and Tua Tagovailoa: Dolphins

Happy Hawaiians! The Dolphins didn’t Tank for Tua but they probably will have to Trade (up) for Tua, who will be off the board before their scheduled No. 5 pick in the Draft. With Tagovailoa’s durability concerns, a veteran caddy is needed. Mariota, the former No. 2 pick in the 2015 Draft, lost his Titans starting job to Dolphins cast-off Tannehill.

Cam Newton and Justin Herbert: Panthers

Newton is a free agent after the season and the former MVP will get a chance to prove his shoulder is healthy while first-round pick Herbert takes a redshirt year to learn the offense. Coach Matt Rhule’s seven-year contract allows for some trial and error in 2020.

Andy Dalton and Jordan Love: Patriots

Now we know why the Patriots were spying on the one-win Bengals in Week 15! To gather intel on three-time Pro Bowler (and zero-time playoff winner) Dalton as Brady’s replacement! He is being pushed out for No. 1 draft pick Joe Burrow and is a free agent after the season, with no guaranteed money in 2020. The Patriots also trade up for the first-rounder Love.

Jameis Winston: Raiders

The relationship between Gruden and Derek Carr runs hot and cold. Signing the enigmatic Winston – off of the NFL’s first 30-touchdown, 30-interception season – will create one of the NFL’s most intriguing competitions. If ever there was a made-for-Raiders quarterback! Too bad HBO’s “Hard Knocks” used the Raiders last season.

Joe Flacco: Bears

If he is cut by the Broncos and will sign on the cheap, he could find a path back to starting by beating out Mitch Trubisky.