Technic History

The Technic History is a Space Opera setting featured in many short stories and novels written by Poul Anderson from the 1950s through to the 1980s.

It spans many centuries of future history, but most of the stories are set in one of two periods:

The Polesotechnic League period (25th century). Most of the stories set in this period feature Intrepid Merchant Nicholas van Rijn, and/or his protege David Falkayn.
The Terran Empire period (31st century). Most of the stories set in this period feature Imperial Intelligence agent Dominic Flandry.

Not to be confused with Anderson's Psychotechnic League series, an entirely separate future history deliberately named in a parallel fashion.

The Technic History provides examples of:

Ape Shall Never Kill Ape: Dominic Flandry is kidnapped by an alien race, who assert that they are far more civilized than the Terran Empire, as they would never betray an oath or otherwise be dishonest (except to other, lesser, races, like humans). He soon has the entire leadership of the planet backstabbing each other, noting that their refusal to admit that they, too, can betray each other if the price is right, is what enabled him to succeed in destroying them.
Bittersweet Ending: Lots. Especially the Dominic Flandry stories; Flandry succeeds, but loses any woman he truly loves, feels guilt at hurting the feelings of the others, and in one story is troubled by the contrast between several honest, decent rebels, who are at best going to be locked up for the rest of their lives, and the decadent, despicable Emperor. The prequel novel had a back-cover blurb which summed up:

Though through this and his succeeding adventures he will struggle gloriously and win (usually) mighty victories, Dominic Flandry is essentially a tragic figure: a man who knows too much, who knows that battle, scheme, and even betray as he will, in the end it will mean nothing. For with the relentlessness of physical law the Long Night approaches. The Terran Empire is dying...

Blue Blood: There are a lot of titled characters in the Flandry stories. He's an aristocrat himself.
Canon Welding: The Nicholas van Rijn stories and Dominic Flandry stories weren't, originally, part of the same universe. But a bit of prodding by fans, and he wrote some bridging so that now they are.
Chivalrous Pervert: Nicholas van Rijn. If you are an attractive woman, expect to have him make constant references to your looks as well as many passes. But should danger appear, you couldn't have anyone better at your side.
Combat Pragmatist: Nicholas van Rijn frequently uses sneaky methods. On one occasion, he taunts an alien prince into biting his behind; the alien prince realizes too late that human biochemistry is toxic to his people.
Even Mooks Have Loved Ones: One of the Dominic Flandry stories ended with Flandry successfully killing a Merseian agent who'd been stirring up rebellion on a Terran world. Then Flandry wondered if the agent had some children who couldn't understand why their father hadn't come home.
Feudal Future: The Terran Empire is more recognisable as using this trope, but the late Polesotechnic league is more literally feudal.
Floating Water: Justified in one of the Flandry novels, with an artificial zero-g environment.
Good Is Not Nice: Nicholas van Rijn from the Polesotechnic League novels is a greedy, sloppy, cynical, womanizing corporate executive. He also constantly saves his employees from death and disaster, often with an elaborate Batman Gambit that involves using evolutionary psychology to psychoanalyze whatever alien race is giving their interstellar trading company trouble. He is also merciful towards his enemies and tries to create win-win situations for them.
Humans Are Warriors: "That race still bears the chromosomes of conquerors. There are still brave men in the Empire, devoted men, shrewd men ... with the experience of a history longer than ours to guide them. If they see doom before them, they'll fight like demons."
Insufficiently Advanced Alien: The Dominic Flandry series has many examples of "barbarians" -- primitive alien species given spaceships and high-tech weaponry by more a advanced civilization, generally for use as expendable mercenaries and deniable proxies.
Intrepid Merchant: Nicholas van Rijn, and his protege David Falkayn.
It Is Beyond Saving: Dominic Flandry has noted that he's just doing his best to stave off the inevitable collapse of the Empire.
The Jeeves: Dominic Flandry's valet, Chives.
Klingons Love Shakespeare: The alien Adzel (who looks like a large centauroid dragon) is a Buddhist (which naturally he learned about from humans). He spent some time on Earth studying human culture.
Last of His Kind: The character Aycharaych, recurring archvillain of the Dominic Flandry stories, is the last survivor of his long-lived, telepathic species. But he keeps it a secret for a long time.
Mixed Metaphor: Nicholas van Rijn, along with malapropisms, often mixed metaphors. Particularly appealing was his reference to forcefully seeking something he wanted "like a bulldozer going after a cowdozer."
Patron Saint: Nicholas van Rijn swears by Saint Dismas (the Good Thief, appropriately), and has expressed the intention of burning candles in offering (to which another character responded "The Saint had best get it in writing").
Planet Terra: The Dominic Flandry stories refer to Terra and the Terran Empire.
Space Opera
Spice of Life: Nicholas van Rijn, something of a throwback to the spice traders of the Dutch East India days, is president of the Solar Spice And Liquors Company.
Standard Sci Fi History: With an emphasis on Step 3, "Interstellar exploration and colonization", and Step 5.3, "Decline and Fall of the Empire".
Stout Strength: Nicholas van Rijn.
Talking Your Way Out: Dominic Flandry. Kidnapped by an alien race, who just assumes he is a decadent worthless low level agent, he soon has the entire leadership of the planet backstabbing each other.
Whole Plot Reference: The Game of Empire is, as aknowledged in the Author's Note, a Gender Flipped, space opera version of Kim.