Hunger Games AUs are essentially fusions in which characters from other fandoms are competitors in the Hunger Games. This is becoming a popular trope in many fandoms, especially those with a OTP or a large cast of potential competitors such as The Avengers.
"Alternate Universe - Hunger Games Setting" tag on AO3
Love What is Behind You by KouriArashi  Fandom: Teen WolfDate: 2017Length: 54k
Basically what it says on the label. Hunger Games type fusion. Stiles doing way better than anyone anticipates. Peter finds him intriguing. Ruthless, devious assholes working together to ruin bad guys, as the Steter
ship is meant to be.
One, two, three by Severus_divides_into_H  Fandom: HannibalDate: 2016–2018Length: 68k
Will imagined his death in numerous ways, numerous times. Being chosen as a tribute opened a road of new possibilities, some more horrifying than the others. He doesn’t want to be torn to pieces like Randall Tier’s prey. He doesn’t want to be burned like Francis Dolarhyde prefers to kill. But most of all he doesn’t want to be caught by Hannibal Lecter, a career tribute with a penchant for eating his victims alive.
Too bad Hannibal seems fixated on him.
Who Painted the Moon Black by throughthedark  Fandom: One DirectionDate: 2013–2015Length: 96k
Hunger Games AU where Louis Tomlinson is district six's victor from the 69th Hunger Games and Harry Styles is district seven's victor from the 72nd Hunger Games.
mercy and death on swift arrows fly by authoressjean  Fandom: The HobbitDate: 2014Length: 27k
He's not supposed to be in the Arena. Kili Durinson is exempt, it's the agreement between District 1 and the Capitol, it's the agreement his uncle made with President Smaug. But he's still been chosen. And the odds of favor don't lend themselves to a young dwarf who's being made an example of as punishment to his uncle.
But there are alliances to be had, strange allies from very different districts. And outside of the Arena, Thorin Oakenshield Durinson is going to do anything and everything to get his nephew back. Even if that means jumpstarting the rebellion.
Embrace the Fire: The Avenger Games by lorata  Fandom: Avengers, MCUDate: 2012–2014Length: 150k
"Trust me, and I'll give you something better than a Mockingjay. I'll give you the Avengers." "What's that supposed to mean?" "Trust me, and you'll see."
Non-powered alternate universe fusion: the Avengers in Panem.
Tributes by TheAvalonian  Fandom: MerlinDate: 2013Length: 87k
It is the 57th annual Hunger Games, and Merlin Emrys stands at the Reaping ceremony with Guinevere Smith at his side, unable to hear the roar of the crowd over the ringing in his own ears. Because Merlin is about to face his best friend and twenty-two strangers in a fight to the death, where there can only be one victor.
In a twisted game where death seems the only certainty, Merlin will find himself tested in ways no one could have ever predicted - and may even find himself fighting for more than just his own life as he enters into an unlikely alliance with Arthur Pendragon, the Career tribute poised to win it all.
child's play by isoscele  Fandom: LumberjanesDate: 2016Length: 48k
In which there is no way in hell Jen will let those kids die in the arena, and she will go to whatever lengths necessary to keep them safe.