It's been a unique 12 months in the history of mixed martial arts. And that's putting it mildly.

The UFC's biggest star, lightweight champion Conor McGregor, didn't make a single appearance -- at least in his own sport. He did make his professional boxing debut, against an all-time great in Floyd Mayweather.

It was a year in which the highest-profile stories tended to circle untraditional topics -- but it also delivered a long list of fantastic finishes and fights.

Here are ESPN's choices for Fight of the Year, Knockout of the Year and Submission of the Year. Stay tuned for ESPN's Fighter of the Year on Jan. 3.

Fight of the Year: Yancy Medeiros def. Alex Oliveira via TKO -- UFC 218, Dec. 2.

Yancy Medeiros defeated Alex Oliveira in UFC 218 at Little Ceasars Arena on December 2. Photo by Gregory Shamus/Getty Images

"I'm here to entertain," Medeiros said after finishing Oliveira with strikes early in the third round.

It's not a false claim. Medeiros has 11 appearances in the UFC and has won performance bonuses in nearly half of those. He won a Fight of the Night bonus in December on the same night all-action lightweights Eddie Alvarez and Justin Gaethje fought each other. No small feat.

Oliveira, of course, deserves equal credit for this bout being what it was. Oliveira was dropped in the opening minute by a left hand. He then dropped Medeiros with a right, one minute later.

Medeiros later said he started a Hawaiian wave for featherweight champion and teammate Max Holloway, who went on to dominate Jose Aldo later in the night.

There were plenty of great fights in 2017 with higher stakes than this one -- but as far as action, momentum and edge-of-seat moments, this is ESPN's choice.

Knockout of the Year: Francis Ngannou def. Alistair Overeem via KO -- UFC 218, Dec. 2

Francis Ngannou of France celebrates his victory over Alistair Overeem of the Netherlands during UFC 218. Photo by Gregory Shamus/Getty Images

Frankly, there are a lot of ways to measure Knockout of the Year -- and probably no "right answer" when it comes to crowning a single one.

Ngannou's murderous left hand at UFC 218, though, was one of the most visually stunning finishes in years. It's the kind of highlight that stays with you.

Per UFC president Dana White, Ngannou has registered punching statistics that are "more powerful than a 12-pound sledgehammer, swung with full force."

Perhaps that's hyperbole -- but after watching the Overeem knockout, who knows? Ngannou challenges Stipe Miocic for the UFC championship on Jan. 20.

Submission of the Year: Demetrious Johnson def. Ray Borg via armbar -- UFC 216, Oct. 7

Demetrious Johnson defeated Ray Borg with an armbar during UFC 216 on Oct. 7 in Las Vegas. Joshua Dahl-USA TODAY Sports

No-brainer here. Not only did Johnson's armbar officially break the UFC's record of consecutive title defenses, it was really, really, really cool.

The UFC's flyweight champion has been so dominant for so long, he's inventing new ways to finish title challengers.

In October, it was a suplex, transitioned into an armbar -- before Borg even touched the ground. Johnson called it a "Mighty Wiz-Bar" -- and hinted he has another submission he hasn't used called "The Mouse Trap."

Immediately after the fight, Johnson's head coach Matt Hume congratulated him on being the "best ever, in the history of the world." Indeed.