Historical characters who appear or are referenced in the timeline:
Napoleon Bonaparte: His father fled Corsica after the French takeover, meaning Napoleon (or his close analogue) grows up in Britain under the name Leo Bone and joins the Royal Navy. Later joins and rules Royal France.
John Byron: Alternate Timeline Brother to Lord Byron, who travels Europe, writes poetry, and eventually becomes a spy for the French army.
Winston Churchill: The Duke of Marlborough is compared to both Churchill and their common ancestor the first Duke. Like Churchill, he is both the saviour of Britain and yet has a dark throwback reactionary streak running through his views.
Adolf Hitler: Michael Hiedler is the Alternate Timeline Brother of Adolf Hitler's real life great-grandfather Martin Hiedler.
After a rebellion by French-speakers in Quebec, the Empire of North America either anglicises (Montréal -> Mount Royal) or outright renames (Quebec City -> Wolfeston) all its settlements with French-sounding names.
Similarly, after adopting Russophile cultural policies to appease those alienated by the earlier Tsars' westward-looking stance, Russia russifies some of its more German-sounding names.
After Corea invades China, they restore the ancient Corean names to every village and city they conquer.
Allohistorical Allusion - A fair few. To take one early example, there is a Battle of Trafalgar fought between Britain on one side and France and Spain on the other—but it's twenty years earlier than the one we know, and Britain loses.
America Saves the Day - For Britain, anyway, since it's still more-or-less part of the *British Empire. In an interesting variation, Spain is saved by *Mexico and its other monarchical former American colonies.
Also inverted. Without being preoccupied by the war against the South American UPSA, the Royal Navy could have defeated the invading fleets of Revolutionary France and prevented the devastation of south-west England.
Balkanize Me - China, Japan and the Ottoman Empire. Also happened to Spain due to the Congress of Copenhagen, with Portugal taking Galicia, Castile as a Portuguese puppet, and Aragon as part of the Crown of the Three Sicilies. Then seemingly turned back around with the New Spanish reconquest of Spain, reuniting most of the country.
Blue and Orange Ideology: A central point of the whole project, according to Word of God, is to show how "Communism VS Capitalism" and economics in general needn't necessarily been the defining ideological issue to risk nuclear war over. In LTTW, the major ideological divide is centered on culture. So it's not just an alternate history, but an alternate historiography.
Call a Rabbit a "Smeerp" - Thande likes coming up with alternate terminology for basically anything invented or discovered after the timeline's Point Of Divergence. Some examples represent older terms from OTL that have survived, such as 'alienist' for psychologist.
Cavalry, The: Heinz Kautzman's Russo-Lithuanian-Danish-Courlandish force in the Battle of Paris.
Conveniently Interrupted Document: Used a few times, especially in Part #100, which at the end is revealed to be the result of the data being corrupted by the radio having been shot mid-transmission.
Deadly Euphemism: "Racial purging", the term in this timeline for what we would call "ethnic cleansing".
Disproportionate Retribution - George II's son Frederick laughes at his father when he trips on the coronation carpet. George's response? Exile Frederick, thus setting up the plot.
Doomed Hometown - A statistically improbable number of the timeline's heroes have their houses, villages, towns, or cities burned to the ground. Well, three, four at the outside, but this has proven enough to make the "Burned House Hero" a fandom running gag and to see the timeline humorously rechristened "Look To The Burning House Where Your Family Used To Live".
Enemy Civil War - *Revolutionary France is plagued by constant power struggles, while Spain had the bad luck to have a bitter succesion crisis just when the French were invading, and Prussia and Saxony fight each other while South Germany burns.
False Flag Operation - The Meridians use the New Spanish flag against the Portuguese in the course of the Popular Wars. This is not without consequences to their national reputation. They get called out on this behavior, even by their own people, and there are worries that the laws and customs of war won't be applied to them by their enemies in future wars.
Frank's 2000 Inch TV: The French engineer Isambard Brunel (the father of the more famous one from OTL) builds a gigantic semaphore shutterbox on the side of a building in Paris capable of displaying 324-pixel images.
Generation Xerox - Once more, we have another British king named Frederick driven from Britain, though this time he is not exiled by his father but rather flees to avoid dealing with Joshua Churchill.
Golem: Golems are very popular in the fantasy fiction of this world, due to the fact that they can be a Recycled IN SPACE! version of Automata set in a mediaeval setting before technology would allow the real thing to be built.
Good Republic, Evil Empire - Inverted, it's republicanism that is currently tarred with the brush of evil (of course, this was somewhat true in the 1810s even in our own world). Partly due to Author Appeal.
Icon of Rebellion: The bloody-red flag with the inverted black fleur-de-lys of the French Revolution, inspired by when the unknown soldier L'Épurateur flew a regime flag upside-down from the top of the Bastille after dipping it in the blood of a fallen reactionary leader.
The United Provinces of South America has the Cross of Burgundy with flipped colours, the Torch of Liberty and later the Sun of Cordoba.
The purple 'Asterisk of Liberty' in Britain, stemming from combining English and Irish cross flags with the newly invented cheap purple tyrine dye associated with 'every man a king'.
Subverted with Le Diamant, who began as a revolutionary leader but whose writings inspired the moderate constitutionalist ideology of Adamantianism, which uses a diamond symbol.
I'm a Humanitarian - Michael Hiedler, who refuses to kill his nemesis personally on the grounds that slaughtering animals for the pot is women's work.
Kneel Before Frodo - King Charles X of France does this at the end of the Popular Wars to his rebellious army as a dramatic gesture that subdues their rage—he also gives all the veterans the right to vote.
Last of His Kind: Emperor Ferdinand IV of the Holy Roman Empire, and he is fully aware of it.
Les Collaborateurs - The Hellfire Club, and others who co-operate, in a little historical reversion, with the occupying French forces.
Moral Guardians / Executive Meddling: In-universe, some of the "Automaton Craze" books of the 1820s-50s are subject to this, such as The Cogwheel Turns, where the original ending (that humans are themselves an automaton creation of an earlier vanished race, identified with legends of pagan gods) was censored.
Furthermore, many history books in this timeline have considerable censorship for ideological reasons, which the crosstime team have to work around.
Multinational Team - Not uncommon as one might expect but the the final stages of the Jacobin Wars aka The War of the Nations is still quite notable because basically every single European nation and the Anglophone North Americans fought against the French Latin Republic.
Non-Nazi Swastika: Swastikas in this timeline are associated with the Etruscan civilisation, as one was found on an unearthed Etruscan artefact and was used as the symbol of an Etruscan-inspired radical movement in northern Italy. In reality of course many, many cultures have used swastikas in their art, but the Etruscans happened to get all the publicity.
One Nation Under Copyright: Most of India is owned by a consortium of European trade cooperations, called International Oversight Board for East Indian Trade, while the Russo-Lithuanian Pacific Company dominates the northern Pacific, including North Japan.
One World Order: The goal of Societism, one of the most influential ideologies of the timeline.
Only a Flesh Wound: When George II leads his troops into the Battle of Dettingen (as he did in OTL) he gets a bullet in the shoulder (unlike OTL), but fights the battle to the end. Averted in that the infected wound kills him some weeks after, leading to the War of British Succession.
Peace Conference: The Congress of Copenhagen is the TTL analogue of the Congress of Vienna.
And then the Congress of Brussels a couple of decades after that. The difference is that this one is marked by more Teeth-Clenched Teamwork, as nationalism has started to take over the European powers' ruling classes, rather than them seeing it as a mutual enemy to all suppress together.
Reassigned to Antarctica: Happens to officials who fall out of favor with their rulers; however, the more typical post is somewhere in the Americas or the East Indies. More visible in the leadup to the Popular Wars.
Republic, The: The Corsican Republic and the United Provinces of South America, the latter also counts as The Federation. The French Latin Republic is a villainous example.
Rightful King Returns - Frederick the First of Great Britain returning from his American exile. The New Spanish repeat it during the Popular Wars, which in the future of the timeline will be written about, appropriately enough, by *Tolkien.
The Return of King Louis XVII to Paris
And the return of the New Spanish Bourbons to Spain itself.
Show Within a Show - Fiction and art have also taken a different course in this world, and some works are periodically mentioned. Most notable is the "Automaton fiction" craze of the 1830s-50s period, which effectively replaces Frankenstein and the rise of vampire fiction in our timeline. (Vampires in this world are considered as obscure as, say, naga or drow are to the general public in our timeline; golems are much better known than our timeline due to authors using them as a mediaeval stand-in for automata in works set in the past).
Space Filling Empire: Lampshaded. A large colonial empire in Africa is actually called the Space-Filling Empire after its two architects, a Mr. Space and a Mr. Filling.
Steampunk - Steam technology has received a boost relative to out timeline, with highly awesome results.
Stranger in a Familiar Land: Frederick, upon returning to Britain and reclaiming his rightful throne, finds that he does not fit in there - having been born and raised in Hanover, and then spending most of his adult life up to that point in the American colonies, echoing the situation of his grandfather, George I (though at least he can speak the language). Voltaire aptly describes him as "an Englishman to the Germans, an American to the English, and a German to the Americans".
Thou Shalt Not Kill - Jean de Lisieux is a dark version of this. A Totalitarian Utilitarian, he believes killing is monstrous because it robs the Republic of a warm body that could be used to build houses or warships in conditions that are slavery in all but name. He will occasionally break his rule for people he considers particularly politically dangerous, but always reluctantly.
In my thoughts I have seen rings of smoke through the trees
And the voices of those who stand looking
Tomato Surprise: Show Within a Show example—The New Eden, the book which started the Automaton Craze in the literature of this world, ends with the revelation that the 'humans' living in the roboticised landscape are themselves automata. This twist is then played with by other books inspired by it, such as The Cogwheel Turns, which suggests that the world is trapped in a cycle in which the dominant race create automata to do their work, grow lazy and decadent, and then the automata rise up and take their place—and the original edition also suggests humans are themselves the creation of an earlier race...
TriadsAndTheTongs, The - The Sanhedui or Heaven and Earth Society, which became the Triads in our timeline, in LTTW realises its original purpose; the Society takes advantage of a Qing dynasty civil war to attempt a Ming restoration...
Unreliable Narrator - Footnotes will occasionally highlight how some of the quoted history books get it wrong, either through lack of knowledge or just plain bias. Most prominently, a common prejudice in the 'present day' of LTTW (excluding some revisionist historians) is that the Japanese are considered subject to Creative Sterility and are intrinsically inferior to neighbouring Asian races, which obviously puts a spin on historical accounts.
War Is Hell: The Franco-Italian front of the Popular Wars is notorious in the cultural imagination for being a bitter, brutal struggle where many lives were spent for little gain: it becomes known as the Nightmare War.
We Are Struggling Together: The Populist uprising in Germany. Theoretically all the groups involved are inspired by Pascal Schmidt and are working to make a united republican Germany. In practice the rebels in Brandenburg refuse to merge with Schmidt's "Volksrepublik Deutschland" which incenses Schmidt—he views them as a bigger threat to Germany than the petty monarchies they seek to overthrow, because all he fought for would be in vain if it just replaces petty feuding monarchies with petty feuding republics and no united Germany.
Wham Episode - The Popular Wars begin in Portugal's colonial empire, of all places.
The 100th chapter ends with the "narrators", a research team from another timeline, being violently arrested by English (no, not British) security forces.