Two members of the Redshirt Army offer to hold back a squad of oncoming hobgoblins in order to give their leader and the heroes enough time to escape. Elan, being Genre Savvy to a fault, knows that they're doubly doomed, and even tells them so in an attempt to dissuade them. They manage to save themselves by giving themselves just enough characterization during the battle, and finally even to downgrade a fatal wound to a minor one by telling each other their names, Kazumi Kato and Daigo. Daigo wisely decides to withhold his last name for a future emergency. As they've both managed to get married, reached sixth level (a "booster level" in any class), and step up to the ranks of nobility afterwards, it's proving to be a prudent move. He even started to reveal his last name: I am Daigo D-(door slams in face)
During the Battle of Azure City, Lien single-handedly defends Hinjo's personal ship from the hobgoblin hordes, both saving it for his escape, and protecting the War Refugees onboard. In a subversion of this trope, she survives, protecting the ship long enough for Hinjo and the Order to get to it and for them all to escape.
In Digger we find Murai, at the temple, alone against an army. With a broken arm.
Murai: Indeed. I have been telling you, have I not, that I believe Jhalm is an honorable man?
In the Festival of Veils arc of Dubious Company, Mary and Sue do this after the Queen threatens to arrest and torture Elly for the King's disappearance. Actually the three of them are mistaking the King for Elly and vice versa. Perhaps the first time Mary has ever looked more badass than her sister.
Tower of God features this when, during the Hide-And-Seek test, Team A, the supposedly stronger Team, resorts to their secondary plan. Everybody tries to stall Quant, who has to catch Anak to fail the team. They fail miserably, all while Quant gives them instruction on how to improve themselves.
"How much time has passed?"
" One minute."
Hilariously parodied in Freefall, where Blunt tried this on Florence, but as a damaged robot, he wasn't nearly agile enough to stop her from running past him, though he thought he'd accounted for that.
"I was sure. Those doors. Opened outward."
In Godslave, when Edith realizes that Blacksmith is out to get Anpu, she tries to hold the line and tells Anpu to run for it. Subverted when she realizes just how out of her league Turner is and promptly follows after the fennec.
In True Villains, Bayn singlehandedly holds a magical barrier against an army of vampires, led by a Time AbyssSorcerous Overlord who is much stronger than him. It helps that he worships the God of Stability, who heartily approves of this trope.
Invoked but averted in Girl Genius: Agatha, Zeetha and a few others from the circus think they're living this trope, but that's only because they don't realize the Jägermonsters are (1) on the scene, (2) on their side, and (3) incredibly badass.
Mage & Demon Queen: The boss demons of the Demon Tower are supposed to do this. But Malori the fire mage has beaten them so many times, they just wave her through now. Also, she's trying to court Velverosa at the top of the tower, and many of them are rooting for her to succeed.