Big Damn Heroes/Literature

Examples of in  include:

The Dresden Files

 * I'm giving one to Harry Dresden for his Dinosaur Rescue, even if he didn't know his people needed rescue.
 * A less major, but still awesome moment is Sanya showing up exactly after an old women says "Oh God in Heaven, help us!". Bearer of Hope indeed...
 * Also, in Small Favor, Michael arrives in the nick of time to save a train station from an army of dark faeries.
 * Being able to do this fairly regularly is pretty much one of the job perks of being a Knight of the Sword

The Lord of the Rings

 * The Hobbit,
 * Bilbo rescuing the dwarves from the spiders.
 * Also, the Lord of the Eagles and his subjects do it twice, rescuing Bilbo and the dwarves from the orcs in chapter 6, then doing so again at the Battle of the Five Armies. But, as Bilbo later learned, they weren't enough; fortunately, Beorn appeared to pull a second Big Damn Heroes, crushing the orc king Bolg and rallying the dwarves' side to victory.
 * The Eagles do this again in Return of the King the Battle of the Black Gate, two of them also rescuing Frodo and Sam from perishing in the eruption of Mt. Doom, though this was a different (though related) group of Eagles.
 * Happens in The Silmarillion too: Luthien saving Beren from Tol-in-Gaurhoth is just one of many examples. Again, the Eagles play this role by rescuing the survivors of the fall of Gondolin and also fighting Morgoth's armies during the War of Wrath. Their King - Thorondor - is the ancestor of the rulers of the previously-mentioned Great Eagles.

A Song of Ice and Fire

 * Sandor Clegane, of all people, gets a moment of this when he cuts through a mob just in time to rescue Sansa from being gang-raped by the rioters. This, naturally, sets up a Bodyguard Crush on Sansa's part and a great deal of Squeeing among the fans, as rescues are wont to do. How heroic he is the rest of the time is up for debate. Arguably, his first Big Damn Heroic moment is actually in the prior book, when his big brother Gregor is about to hack a stunned and helpless Loras Tyrell in two...only for the Hound to show up just in time to divert the killing blow and defend Loras till Gregor cools down. More humorous considering he's, you know, rescuing the Ambiguously Gay Loras Tyrell.
 * Nothing ambiguous about that - George R. R. Martin has confirmed that yeah, Loras was knocking boots with Renly Baratheon.
 * Sandor's not the only Big Damn Hero in the series. Who can forget Jaime Lannister, completely unarmed, leaping into a bear pit to distract said bear from Brienne? Of course, Jaime doesn't manage to do much about the bear on his own, but the archers he brought back with him do. Made even better by Jaime's quip, after he asks if Brienne is still a maiden: "Oh, good. I only rescue maidens."

The Time Scout series

 * In Time Scout, Kit and Malcolm come to 16th century Darkest Africa to rescue Margo and Kynan from Portuguese soldiers.
 * Subverted in Wagers of Sin when Skeeter crashes the Porta Romae just in time to rescue Marcus after a mad dash across La La Land. Also present is Lupus Mortiferus, who brutally clubs Skeeter down.
 * Played straight a few weeks later when Skeeter finally rescues Marcus and takes him home.
 * In Ripping Time, Armstrong shows up just in time to save Jenna from Jack the Ripper.
 * In The House That Jack Built, Kit and Skeeter catch up to Paula Booker and some guides being pinned down by native bandits outside Denver.
 * Also in The House That Jack Built, Skeeter tracks down his new adopted family after many weeks of searching so that he can help rescue them from The Syndicate.

Other works

 * Zaphod Beeblebrox in The Hitchhiker's Guide to the Galaxy does this enough that in And Another Thing it's Lampshaded by Ford Prefect who comments on Zaphod's unfailing ability to be in exactly the right place at exactly the right time.
 * John Moore's Slay and Rescue opens with Genre Savvy hero Prince Charming (that's actually his name) carefully timing the rescue of a princess to achieve this effect. It's part of the job.
 * In City of Glass Jace saves Clary from being killed by the big bad.
 * In the fifth Young Wizards book, this happens when the Lone Power is giving Nita Its Evil Gloating speech. She's just about ready to give in...when her wizard partner Kit bursts in in the nick of time. "Fairest and Fallen, one more time...greetings and defiance." You can practically hear the epic music.
 * In Bill Baldwin's Helmsman series, the final battle of the first book is the protagonist having to hold off three ships. He actually thinks about this trope, about how the BDH only arrive on time in books. Of course, since this is a book, a few cruisers do arrive - when half his crew is dead and the ship is good for nothing but scrap (and only half an enemy ship remains).
 * Malik ibn Ibrahim does this from out of nowhere in the second story in the anthology Wandering Djinn.
 * In the Dale Brown novel Air Battle Force, is about to be killed by an usurper when Chris Wohl in a Tin Man Powered Armor suit shows up and evens the odds in preparation for . In Plan of Attack the same chap gets saved again, this time from Russians.
 * In the Malazan Book of the Fallen the Barghast and the Bridgeburners get this when they save Capustan from the Pannonians.
 * In the second Empire From the Ashes book, . Curb-stomping ensues.
 * While Chip was not in direct physical danger during his trial in The Rats, the Bats, and the Ugly, the rape charge based on a (falsified) deposition was both the strongest and most likely to have him hung. Then the supposed victim unlocked the courtroom doors with a chainsaw and kicked them open before declaring Chip's innocence.
 * Odd example in Chronicles of Amber that stradles the line between this trope and Villainous Rescue: Corwin, the hero, is the one doing the rescuing--and he only decides to pitch in the moment he gets there. Prior to that, he intended to attack Amber himself.
 * Near the end of Terry Pratchett's Discword novel ''Monstrous Regiment" when the Ins and Outs are about to be packed off and safely out of the officers' hair. Sgt Jackram bursts through the door to defend his . What with him being larger than life (some think literally) and having about 40 years of blackmail material in his head, he begins an epic verbal beat down of the entire general staff to free his troops.
 * The Secrets of Droon - So, our kids are trapped in a room with rising water filled with poisonous serpents. They're all resigned to their fate. And then,  appears literally out of nowhere and magics the serpents out of existence.
 * In Robert E. Howard's "A Witch Shall Be Born", Conan the Barbarian arrives just as a fight between the usurper's forces and the loyal subjects who just learned of the Fake King is breaking out.
 * The Landreich forces in Fleet Action, during the Battle of Terra, jump in at the last minute to save Earth from being made uninhabitable by "dirty" nukes.
 * At the end of Wrath of the Lemming Men, Space Captain Smith returns to his comrades on New Luton with as his new allies, turning his hard-pressed colleagues' struggle for survival into a Curb Stomp Battle against the enemy.
 * In The Brief Wondrous Life of Oscar Wao, Belicia (Oscar's mother) ran afoul of someone powerful in Trujillo's regime in her adolescence and some secret police thugs tried to force her into their car. She barely managed to call for the help of her old boss, a Chinese immigrant named José Then, as he was passing by. When he saw what was going on, he was on the thugs in an instant, handgun pressed against one's skull and the determination to use it, personal danger be damned. Beli later told her daughter, "Mis chinos saved my life."