An alliance in Escape the Night is when 2+ people agree not to vote for each other or are always siding with each other during votes. The latter could be because of them being close friends outside of the show or related to each other or dating.
List of Alliances
Season 1
Timothy DeLaGhetto and Matt Haag (ep 1-6)
Tim and Matt would always gravitate and joke with each other during the show and agreeing with each other on votes until episode six, where Matt gave up after accidentally killing Sierra in the death challenge. Both were voted into the Dollhouse Challenge, where Matt drank two rounds of poison and died, allowing Tim to get the antidote.
Joey Graceffa and Lele Pons (ep 4-9)
After the Perverse Games, Joey defended Lele and kept Matt from voting her in. He kept this going until the Final Four, where he was Lele's partner after she was voted into the Ring Toss Challenge with Oli, who had Eva as his partner. Joey failed to get three rings on the metal pegs that resulted in Lele's death.
Season 2
Alex Wassabi and Lauren Riihimaki (ep 1-2)
Alex and Lauren were dating at this time and stuck together during these two episodes, with the exceptions being when Lauren was taken by a vampire and when she was voted into the Golden Goblet Challenge.
In Season 4, DeStorm would throw a challenge in favor of Alex to apologize for Lauren's death.
Gabbie Hanna and DeStorm Power (ep 1-4)
Tyler Oakley, Alex Wassabi, and Tana Mongeau (ep 6)
Also known as the TAT alliance, Tyler, Alex, and Tana finished finding their spell ingredients and waited for Gabbie, Andrea, and Joey. The alliance was short-lived, as Tana was betrayed by Joey and Andrea, causing the Path of Betrayal Guardian to kill her.
Joey Graceffa and Tyler Oakley (ep 8)
Another short-lived alliance, this one didn't end at a vote and death, but ended when Tyler broke Joey's bottle in the Gauntlet.
Season 3
Nikita Dragun and Manny MUA (ep 1-9)
Also nicknamed the Mean Girls by Joey after Safiya's death, these two have been good friends outside of the show and naturally teamed up. Voted into challenges against each other multiple times, the alliance ended when Nikita was given a choice in the Straightjacket Key Hunt: kill Manny or kill herself. She shot Manny several times.
Matthew Patrick, Rosanna Pansino, and Safiya Nygaard (ep 1-6)
Also known as the MRS Alliance, these three friends naturally came together and protected each other. This alliance was destroyed in a plot twist with the Funhouse Challenge, where the person who voted in the winner would die instead. Since Safiya voted for Nikita, Safiya was the one who died.
Matthew Patrick and Rosanna Pansino (1-8)
Also known as the Soul Siblings, MatPat and Rosanna were an alliance within the MRS Alliance. This alliance was broken up by Ro being sacrificed by the Witches, all so Maria could regain her youth and be reunited with her brother, Sam.
Season 4
Alex Wassabi and DeStorm Power (ep 1-4)
An unlikely alliance, these two teamed up until the Emporer's Challenge, where DeStorm cheated on purpose so that Alex could continue on.
Joey Graceffa and Colleen Ballinger (ep 3-7, 8-10)
Colleen started out despising Joey, but when Joey gave her enough gold coins to be safe from the death challenge, she changed her tune a bit. When he promised to get her out of Purgatory so she could be with her new son, she sided fully with him. However, this alliance was nearly destroyed when Colleen died in the Minotaur’s Maze Challenge. Luckily, Joey was able to resurrect Colleen when given the chance and the alliance reunited. This allowed Colleen to escape Purgatory with Bretman, however, Joey was enticed by the power of Pandora's box and stayed behind, breaking the unlikely pair apart forever.