Erron Black's round win animation consists of him taking a coin out of his pocket, flipping the coin, and then putting it back. However if you hold Up while this happens, he will toss the coin at his opponent and say "Keep the change".

This Easter egg was hinted by NRS senior designer Aaron Davis back in October 2020 and it wasn't discovered until February 2023.
Contributed by ZpaceJ0ck0
In an intro conversation between Spawn and Scorpion, the former will ask the latter if he has been to other dimensions, to which Scorpion replies with "each has had its own injustices". After that Spawn will say that "Maybe that's why my soul still burns".

This is a reference to Spawn and Scorpion's guests appearences in SoulCalibur II and Injustice: Gods Among Us, respectively.
Contributed by ZpaceJ0ck0
According to English voice actor Sean Chiplock during a 2020 Reddit AMA, he was asked how did he get to voice Noob Saibot. He responded:

"Pretty much the same as I potentially get any other role; my agency sent me audition sides for the character, I submitted my audition takes, and the client decided they liked one of them enough to cast me! The character/project was codenamed at the time so I didn't know what it was for, but the specs asked for something "wraith-life and not of this world". So for the first take, I did something higher pitched and ghostly, with a little bit of teeth; for the second, I impersonated Black Doom from Shadow the Hedgehog's game on GameCube, and aimed for a baritone demonic rumble."
Contributed by ProtoSnake
English dub voice actor Karen Strassman, known for Kitana & Mileena from Mortal Kombat (2011) and Mortal Kombat X, did not return to voice her characters for Mortal Kombat 11, citing internal politics in the gaming industry that affected the game's casting.
Contributed by ProtoSnake
One of Shao Kahn's intros he will say to the Kollector is "Let us make Outworld great again", referencing "Make America Great Again", the campaign slogan of former American president Donald Trump.
Contributed by ProtoSnake
NetherRealm Studios was able to get the likeness rights of Arnold Schwarzenegger for the Terminator guest character, but he was not able to provide the voice for the character. Instead, Schwarzenegger himself chose voice actor Chris Cox to be hired to voice the Terminator according to senior UI artist Daanish Syed.
Contributed by Pogue-Mahone
The name of the main boss Kronika may be a reference to Chronos, the personification of time in pre-Socratic philosophy, often mistaken with the ruler of the Titans in Greek Mythology, Cronus. While this is a recurring historical and philosophical mistake, this might have inspired the idea that Kronika is a Titan, much like Cronus. Additionally, the word "Kronika" is a Czech and Slovenian cognate which translated to English means "Chronicle".
Contributed by lewiesell6605
An intro conversation between Liu Kang and Sub-Zero references the Mortal Kombat movie, after the latter asks "What did Kitana tell you?", Liu Kang replies "All I need is a pail of water", the method in which Liu Kang defeated Sub-Zero in the film.
In an intro conversation between Sub-Zero and Raiden, after the latter says he had a dream of a "strange and unjust world", the former will reply, "With a dark knight and a caped Wonder?", a reference to Injustice 2, in which the two appeared as DLC fighters.