Smoke & Sub
Shang & Quan
Liu Kang & Kung Lao
Scorpion & Quan
Noob & Smoke
Kenshi & Sub
Quan & Moloch/Drahmin
Kabal & Stryker
Goro & Kintaro
Johnny Cage & Jax
Sektor & Cyrax
Sub & Quan
Kano & Kabal
Havik & Noob (lulz)
Shujinko & Nightwolf
Ermac & Kenshi
Mavado & Daegon
Kano & Shang
Fujin & Raiden
Bo Rai Cho & Kung Lao
Shinnok & Quan

Wow, Quan Chi really gets around.

Did I miss any?

Too bad he ended up stabbing everyone you listed in the back. Why any character would trust him as an ally would be beyond me at this point. While I love him as a character I would like to see how he ends up getting killed (if he ever does) in MKX.

Reiko & Rain.

Johnny and Liu in the movie tbh.

Kano and Quan Chi just being real lol.

Noob Saibot and Havik; NRS please do not give up on this bromance.

Noob will probably fight SZ at some point in MKX and Havik dislikes every form of control. A cryomancer freezes physics so SZ and Havik are natural enemies.

I like Liu Kang and Kung Lao but my favorite would be Kung Lao and Fujin. I loved that they teamed up in Armageddon but I'm pissed we never get to see it. My two favorite characters teaming up and it's never shown and will most likely never happen now because they rebooted the story.

Kabal and Stryker - These two make the best crime fighting duo.

Liu and Johnny - Johnny is the funny man and Liu kang is the straight man.

Jax and Cyrax - They're both black, all black guys are friends.

Reminded me of this:
https://www.youtube.com/watch?v=tbud8rLejLM
(everyone should check this)

The #1 bromance in MK is Liu Kang and Kung Lao, hell they even dedicated an entire adventure game to that relationship.

A very close second would be that of Sub-Zero and Smoke, however, with a lackluster way of showing off their story and their history together, we cannot fully realize how Smoke's friendship with Sub-Zero saved Sub's life from Cyrax and Sektor.

I always felt that when the Earthrealm warriors get split up, Raiden and Johnny Cage always happen to be paired together. It appeared that way in MK9, but even as a kid growing up I always felt that was the case. It's an interesting relationship. Wise cracking mortal, with an all too serious and concerned god.

Kenshi and Ermac are a good duo.

It's not really a bromance, but Jax and Sonya have a platonic relationship and they're a kickass special forces team. Jax traveled to a different realm just to get his team member back.

Quan Chi was one of my favorites in Deadly Alliance but now it's just reached troll status and he desperately needs that comeuppance. My money is on Shinnok, Scorpion, or Raiden.