What is a trope?
Tropes are recurring writing devices and conventions that can be expected to be present in readers or viewers minds as they read or watch stories. The are not intended to be clichés or trite stereotypes, although they may become those things through overuse.
There is a website that lists and identifies tropes associated with movies and television series called http://www.tvtropes.org.
One of the pages of this site lists tropes associated with Brokeback Mountain.
http://tvtropes.org/pmwiki/pmwiki.php/Main/BrokebackMountain
A slightly edited list of tropes identified with BbM on this site are as follows:
Absence Makes the Heart Go Yonder: Jack and Ennis start new families after leaving Brokeback Mountain; however, they soon return, despite only much later seperating (legally and emotionally) from their wives.
Adaptation Expansion: The movie goes into more detail on the men's lives apart from each other, particularly Ennis'.
Adaptational Attractiveness: Del Mar and Twist aren't described as being particularly good-looking in Proulx's short story. They're played by Heath Ledger and Jake Gyllenhaal.
Ambiguously Gay: The men themselves. It's clear they're in love with each other, but debate rages over whether it's a Single-Target Sexuality or if they were simply too closeted to ever be with other men. The fact that Jack solicits a male prostitute down in Mexico leads many to believe he's gay, whereas Ennis' sexuality is much more ambiguous.
From the short story: "Ennis pulled Jack's hand to his mouth, took a hit from the cigarette, exhaled. "Sure as hell seem in one piece to me. You know, I was sittin up here all that time tryin to figure out if I was-? I know I ain't. I mean here we both got wives and kids, right? I like doin' it with women, yeah, but Jesus H., ain't nothin' like this. I never had no thoughts a doin it with another guy except I sure wrang it out a hunderd times thinkin about you. You do it with other guys? Jack?"
*beep* no," said Jack, who had been riding more than bulls, not rolling his own.
Ascended Meme: The "Brokeback Whatever" parodies on Youtube—from Brokeback to the Future to Star Wars: The Empire Brokeback to...well, you can look around. There's a LOT of them, and most of them are surprisingly funny.
Bury Your Gays: Jack is killed in what is said to be an accident, but Ennis suspects otherwise. Somewhat justified due to the setting and time period. A key reason Ennis keeps his feelings close to the chest is because as a child he literally saw what became of a gay man who didn't hide his orientation (and doesn't even discount the possibility his own father helped kill the man); this is why when he is told of the accident that killed Jack, he sees in his mind a similar killing as what really happened.
The Beard: Both boys have them. But whereas Lureen dispassionately manages Jack's accounts and is semi-aware of his habits, Ennis neglects and resents the women in his life.
But Not Too Gay: A common complaint is how little screen time the intimacy between the men got compared to the relationships to their wives.
The Coroner Doth Protest Too Much: Jack while "fixing a flat."
Cowboys: The job they took was sheep herding, of course, but they do fit the trope in that Ennis is a working cowboy and Jack is a rodeo rider.
Clint Squint: Ennis's departing scene with Jack. "Now you listen here *beep*
Defrosting Ice Queen: Inverted with Lureen, who frosts up as the years pass.
Downer Ending: Excuse me... I have something in my eye.
Everyone Remembers the Stripper: The way people talk about this movie, you'd think it consists solely of Heath Ledger and Jake Gyllenhaal having sex in a tent, plus a part with Anne Hathaway topless.
Everything's Worse with Bears: As Ennis can attest.
Flashback: Two — Ennis' childhood memory of being taken to see the remains of a murdered gay man, and Jack's memory of Ennis holding him during their summer on Brokeback.
Gay Cowboys: one of the most famous examples. Except that they're shepherds.
Gayngst
Good Parents: Jack's Mother, as far as we can tell. When Ennis shows up after Jack's death, they seem pretty clear on what his relationship was with their son, while Jack's father makes it clear he viewed his son as a failure, Jack's mother clearly devastated at her son's death welcomes Ennis. She asks him to come back someday and visit and lets him take Jack's shirt even placing it in a bag for him.
Have I Mentioned I Am Heterosexual Today?: Basically their entire cultural background demanded it as an absolute.
I ain't queer.
If It's You, It's Okay: Possible explanation of Ennis's feelings for Jack.
IKEA Erotica: The tent scene. Anyone who tries anal sex like that is in for a world of hurt.
Innocent Cohabitation: Jack and Ennis on their first trip to Brokeback Mountain.
Lie Back and Think of England: Judging by Ennis's sexual position with Elma.
Long Distance Relationship Love Triangle: Ennis is loved by both Jack and Alma. (It's unclear when Jack's wife Lureen found out about the relationship he has with Ennis, and it isn't as important to the plot.).
New Old West No Bisexuals: Some people are annoyed that this is referred to as they gay cowboy movie and Jack and Ennis are commonly called gay, when in fact they may well be bisexual. Bisexual activists have used this movie as an example of 'bisexual erasure'.
Playing Against Type: Anne Hathaway as Lureen; this was one of several roles that moved her away from the Contractual Purity reputation she had at the time.
Pornstache: Jack grows one in later years.
Reunion Kiss: After seeing each other for the first time in four years, they try to stick to a simple Man Hug - and then Ennis proceeds to slam Jack up against the wall and kiss him like he'd die the second he stopped. It's just a little heartwarming... *sniff*
Sliding Scale of Idealism Versus Cynicism: With regards to their relationship, Jack is closer to the idealistic side, believing that he and Ennis could have a happy life together as a couple. Ennis is more cynical, due in part to his greater awareness of societal prejudice.
Star-Crossed Lovers: Ultimately, it's society that keeps the men apart more than anything else.
The Stoic: Ennis, though this is played with as being something of a mask.
Too Good For This Sinful Earth: Jack. He never cared about money and just wanted to live in a cabin with Ennis.
Transparent Closet: They're so not subtle when they're together.
And by the end of the movie, it seems like Jack's parents and wife knew.
Unreliable Voiceover: When Lureen tells Ennis how Jack died, we see the (probably) real story, but Word Of God says that it was left "deliberately ambiguous".