It’s called the Dream Factory for a reason.

Hollywood has been churning out movies about dreamers for decades, and this year’s best picture contenders follow that cinematic tradition: Dreamers abound on screen and behind the camera.

Cleo, the indefatigable domestic at the center of Alfonso Cuaron’s “Roma,” seems to yearn for her own family while placidly caring for her single-mother employer and brood. But after fate (and a particularly toxic rat bastard of a boyfriend) undo what we thought were Cleo’s dreams, a day at the beach reveals she’s felt a part of a family all along. Her deepest instincts are to protect those children, one of whom will grow up to be the auteur, who will struggle for years to shape and finance a black-and-white, English-subtitled, stunning and highly personal tribute to a poignant life of self-sacrifice.

In two history-based epics it’s the powers behind the throne, rather than the throne-sitters themselves, who possess big dreams and act on them. The chance of becoming “The Favourite” to dotty, despairing Queen Anne sets in motion director Yorgos Lanthimos’ battle between feral Sarah Churchill and at-loose-ends cousin Abigail Masham, a series of audacious chess moves that make “All About Eve” look like “Won’t You Be My Neighbor?” Yet what other recourse is available to a woman in the early 18th century, especially one of no means? “I must take control of my circumstance,” Abigail says. “I’m on my side, always. As it turns out, I’m capable of much unpleasantness.”

So is Lynne Vincent three centuries later in Adam McKay’s raucous picaresque “Vice,” and for the same reasons. “I can’t run a company or be a mayor, that’s just the way it is for a girl,” she snaps, laying it on the line to her “big fat piss-soaked zee-ro” of a fiancé: “Either you have the courage to become someone, or I’m gone.” “I won’t ever disappoint you again,” enigmatic Dick Cheney promises Lady Macbeth … er, Lynne, adopting her dream and riding his oath all the way to the White House. Each filmmaker took an enormous gamble — Lanthimos, shepherding a femme-centric period story; McKay, jumping squarely into the fray of a polarized national body politic — to forge a one-of-a-kind experience people love or loathe, but rarely in-between.

Two dreamers have the courage to become someone on concert stages: legendary Freddie Mercury, hot to merge opera with camp and elevate rock in “Bohemian Rhapsody,” and fictional Ally Campana, siren-songwriter par excellence of “A Star Is Born.” Each faces the same obstacle: physical appearance. Ally to rock star: “Every single person that I’ve come in contact with in the music industry has told me that my nose is too big and that I won’t make it.” Freddie to prospective bandmate: “You’ll need someone new. … What about me?” “Uhh — not wi’ those teeth, mate.”

Yet in both cases, talent and luck lead to triumph. Pundits were ready to dismiss novice Bradley Cooper as an ego-tripping dilettante, until they saw how sensitively he understood the live-performance milieu and addiction, and a directorial star was born. Bryan Singer’s dismissal during production seemed set to sink “Rhapsody,” until an incessant, Dolby-juiced stomp-stomp-CLAP confirmed that whoever was helming, they would — they would — rock you.

Race relations, surely the most contentious issue of our time, preoccupy the remaining nominated dreamcatchers. Spike Lee’s “BlacKkKlansman” centers on real-life Ron Stallworth, the Colorado Springs police department’s Jackie Robinson circa 1978: “I’d like to be an undercover detective,” he tells his chief. “I’m young, there’s a real niche for me — and I hate the records room.” The influence of girlfriend Patrice and activist Kwame Ture starts to radicalize him, and the assignment to infiltrate white supremacy becomes a mission. “Doesn’t that hatred you’ve been hearing the Klan say, doesn’t that piss you off?,” he demands of his reluctant Jewish partner. “Then why you acting like you ain’t got skin in the game, brother? … It’s our business.”

Peter Farrelly’s “Green Book” goes back even earlier, as African-American pianist Don Shirley dreams of cracking institutional racism in an eight-week road trip playing Deep Southern concert venues circa 1962. “It takes courage to change people’s hearts,” his trio’s cellist Oleg tells chauffeur/bodyguard Tony “Lip” Vallelonga, whose initial dream is simply to get the job done and join his Bronx family for Christmas. Venturing out of the safety zones set by the titular travel guide, an elegant yet emotionally distant virtuoso and a crude yet vital goombah find common ground and wind up — yep — changing each other’s hearts.

Ryan Coogler’s “Black Panther” boasts a complex dream scenario, revolving around two cousins with plausible claims to the Wakandan throne, fighting as much for their ideas as for personal power. “All over the planet, our people suffer because they don’t have the tools to fight back,” says N’Jadaka (aka Killmonger) of his plans to stockpile vibranium and turn the tables on the oppressors. By contrast, T’Challa’s platform is unity over division, speaking as much to present-day America as to Wakanda: “In times of crisis, the wise build bridges while the foolish build barriers. We must find a way to look after one another as if we were one single tribe.” Each man is the other’s implacable obstacle, in perhaps the first-ever superhero spectacle in which one might genuinely root for the nominal villain.

Not surprisingly, these filmmakers all had to overcome prejudice to achieve their outsized visions. Lee, sometimes pegged as an undisciplined storyteller, conveys his signature consciousness-raising rage through his career-strongest narrative to date. Farrelly’s lighthearted resume caused many to expect a dumb-and-dumber “There’s Something About Racism” rather than a gentle stab at humane reconciliation. Coogler and T’Challa together combatted skepticism that a black superhero — let alone a black director — could dominate the Marvel Universe, each proving that nobody does it better.

All eight nominated movies arrived at the finish line against difficult, even impossible odds, ready and able to feed the dreams of those of us sitting in the dark.