Sam Gamgee in the Lord of the Rings, for most of the first book he moans about the lack of rope.
In fact hobbits as a whole, Bilbo outfits Frodo in case he gets stabbed (justifiable under the circumstances, but none of the other hobbits have armor) and in The Hobbit Bilbo also considers a pocket handkerchief an essential part of a dragon-hunting adventure.
Tom Clancy's Executive Orders: After the U.S. is attacked by a Japanese terrorist, President Ryan happens upon the contingency plan to attack Japan. He orders it destroyed. The narration notes they're just going to file it away.
He has quoted Foghorn Leghorn on one occasion when he pulled something similar out of thin air, as he's wont to do. Much like Foghorn, it's not so much a case of being Crazy-Prepared as it is of being Genre Savvy and always keeping a little something in reserve.
Crazy-Prepared, and also Properly Paranoid. He really does have a whole lot of powerful, ruthless enemies. He almost never leaves home without a bulletproof leather jacket and magic rings that can release enough force to flip a car.
Harry: Paranoid? Maybe. But just because you're paranoid doesn't mean there isn't an invisible demon out there waiting to eat your face.
He carries water balloons filled with holy water in a box under the driver's seat of his car just in case he gets jumped by vampires while parked. He also carries an enchanted chain with an electrical plug designed to be flung at an enemy and then connected to an outlet as a magical taser in case he gets attacked indoors, which he can smoothly and effortlessly draw thanks to practicing the draw thousands of times. He even built what amounts to a voodoo doll of the city of Chicago to use as a focus to track down bad guys running around in his town.
After a nasty incident involving a Dangerously Genre Savvy villain who figured out that since his shield spell only blocked kinetic force, throwing enough fire at him would still cook him, shield or no, he made a new one that would block everything he could think of that it would be even remotely possible for someone to throw at him.
In Cold Days, we find that Molly, his apprentice, is also this. Not only does she anticipate that Harry will come back to life, but she's actually set aside a room in her apartment for him to crash in when he does, his house and legal identity being more or less gone. Also crosses over with Genre Savvy; their world is an Urban Fantasy stuffed to the gills with tropes, and what trope is older than the protagonist coming Back from the Dead?
Although the short story Bombshells actually gives her a reason for knowing that; Lea told her.
Donar Vadderung, CEO of Monoc Security, keeps his base stocked weaponry to fight any war. The selection goes from sharp sticks to top-of-the-line modern small arms, and there's enough of each to outfit an army. He also recruits only the most competent staff, and maintains a excellent spy network. His secretary explains that "one can only have as much preparation as one has foresight". Of course, the fact that Vadderung is in fact Odin, and by a strange turn of events, Santa Claus, explains a lot of things.
The White Council has standard paperwork for if a warden comes back from the dead. It doesn't get used often (it's beyond the abilities of any human wizard), but Rashid thinks he "remembers all the necessary forms.”
The Zhangs of The Heroes of Olympus have an armory in their attic that's almost as well stocked as the one at Camp Jupiter. They have everything from swords, bows, arrows, spears, even potato launchers for taking out earthborn. It comes in handy. (Don't forget the water-hose on the roof!)
The Survivalist, hero of the 1980's action novel series by Jerry Ahern. Ex-CIA agent John Rouke has a well-stocked underground retreat enabling him to survive not only World War Three, the collapse of society and Soviet occupation, but later the extinction of all life on Earth!
Jarlaxle, from R. A. Salvatore's The Legend of Drizzt books, has a hat containing a portable hole, a feather on the hat that summons a giant bird, an infinite supply of knives, a belt that can turn into a snake or extend into a rope, an eyepatch that can see through walls and also protects him from mental intrusion, boots that can silence his footsteps, a ring that can hurl fireballs, a cloak that makes him immune to projectile attacks, several magic wands, a maul hidden in his hat, a ring that detects lies, and a ring that protects from fire or ice. Do not underestimate Jarlaxle.
World War Z. White South African Paul Redeker had been hired by the government to come up with contingency plans in case of a large-scale revolt of the native African population (called Plan Orange). When the Zombie Apocalypse occurred, Redeker went to his mountain retreat and, on his own initiative, adapted Plan Orange into a national zombie survival plan. Most governments in the world implemented his plan and eventually survived the war. Not forgetting the first book, The Zombie Survival Guide, which taught the average Joe how to survive a zombie attack, with advice about forming groups of people, securing secluded land and, naturally, hoarding food, materials and weapons. It's noted in WWZ that it's useful mostly for Americans. Since the "interviewer" is Brooks himself, this is Self Depreciation.
Ironically, however, the US Military somehow contrived to have both covert zombie-fighting operations and to be completely stupid when the Battle of Yonkers rolled around. The people responsible for the covert ops were planning to be prepared, but ran out of time. note Specifically, they needed to build up their forces first. Critics of the book have claimed that zombies should be a cakewalk to even unprepared modern military forces, even including what basically amounted to "DM Hax".
The level of Crazy-Prepared going on in The Zombie Survival Guide is hard to imagine for anyone who hasn't read the book. It can probably be safely said that Max Brooks thought of everything when compiling that book. He has strategies and tips for fighting zombies in every conceivable type of terrain (including watching out for zombies who had been frozen under snow or ice during the winter and are now starting to thaw). And, in the chapter on the pros and cons of various vehicles, he even includes tips regarding the use of Lighter-Than-Air vehicles, like blimps and hot air balloons.
Mouse, the central character of The Eighteenth Emergency by Betsy Byars, spends his spare time working out plans for dealing with various emergencies, such as being bitten by a tarantula or attacked by a tiger. He is a 12 year old who living in suburbia. The premise of the book is that there's an 18th emergency he hasn't prepared for; being beat up by a bully. If you must know, he gets his head handed to him.
In Through the Looking Glass, Alice meets the White Knight, who is crazy prepared (emphasis on crazy!). He has a mouse-trap on his horse's saddle and his horse wears anklets to prevent shark attacks. He keeps the empty plum-cake plate Alice is holding, just in case they find any plum-cake.
Etjole Ehomba, central character of Journeys of the Catechist by Alan Dean Foster, carries any number of magical and alchemical gifts in his backpack. Most of these are intended for use in other applications, but prove effective in whatever crazy-ass situation he's currently facing as well. In addition, his "sky-metal sword" usually has a hidden ability perfect for whatever foe he's fighting.
In Good Omens by Messrs. Gaiman and Pratchett, the International Maritime Codes include an eight-letter code (XXXV QVVX, if you're really curious) for "Have found Lost Continent of Atlantis. High Priest has just won quoits contest."
Crowley, a demon, keeps a flask of Holy Water on hand, just in case.
Truth in Television (or literature in this case): an essay in the 28 July 1934 issue of The New Yorker was entitled "Melancholy Notes on a Cablegram Code Book" and it mentions a bunch of these sorts of code groups in a commercial (non-secret) code. Such as LYADI, meaning "Arrived here with decks swept, boats and funnels carried away, cargo shifted, having encountered a hurricane." Or EWIXI, "Very few cases of cholera are now reported". As the essay's author mentions, some of them are just a little too disturbingly detailed.
The protagonist of H.P. Lovecraft's "The Shunned House" suspects that he has discovered a vampire, but knows better than to rely on a wooden stake and hammer, instead bringing a pair of flamethrowers and a Crookes tube, "in case it proved intangible and opposable only by vigorously destructive ether radiations". This being a Lovecraft story, it turns out neither of these are appropriate weapons for what's actually going on.
Vorbis, antagonist of Small Gods, had a very weird form of planning which was described as such: "You had to have a mind like Vorbis's to plan your retaliation before your attack." In other words, he planned an assault on Ephebe (with resultant tragic losses) only after starting an even more elaborate means to get back at them first.
Mr Teatime, an assassin in Hogfather, made a hobby of working out ways to kill anthropomorphic personifications, such as the Hogfather, the Tooth Fairy or even Death. This came in very handy in his next contract.
Vetinari, the Dangerously Genre Savvy Patrician of Ankh-Morpork, knows that when a ruler is overthrown the overthrowers tend to lock the ruler away in the deepest, dankest cell of his palace's dungeons. Hence, Vetinari ensured that while the deepest, dankest cell's door has a heavy-duty lock on the outside, all of the deadbolts and bars are on the inside. He also has the key hidden behind a brick in the cell wall so escape can be performed at leisure. Training the local sentient rats to run errands didn't hurt either. Yes, the Patrician arranged for his jail cell to have room service.
The Lancrastian Army Knife contains everything a soldier in the field could need. The trope is played with, as it's explained that if it had contained absolutely everything a soldier might need, it would have been too big and heavy to carry around, so most of the suggested items (such as a "small tool for winning ontological arguments") had to be left out.
Commander Vimes has liberally booby-trapped his home and all non-direct entrances to his office, knowing that various individuals would be contacting the Assassin's Guild about removing him from office. The effectiveness of these precautions (and his increasing importance in Ankh-Morpork's political landscape) has resulted in the Guild refusing to take any more contracts out on him. These days, the Guild uses him as a training objective for know-it-all students: all the trainee needs to do is get a glimpse of him without getting caught by a trap. So far, nobody has succeeded.
In Pyramids, Pteppic gears up for his final exam at the Assassins' Guild with so many weapons, housebreaking tools, and protective items that he falls over when he tries to move.
Doc Savage has a spyhole and control panel within his private elevator that can start a film projection of him getting killed in a selected way (machine gun, acid, explosion etc.) onto the lobby door of the elevator before it opens to fool anyone who would ever try to personally attack him in the lobby of the Empire State Building. It is only used once in 16 years.
In fact, many, if not most, books in the series contain examples of this trope.
Hermione, from Harry Potter, but she's only Crazy-Prepared in comparison to Ron and Harry, who barely pay attention even in self-defense classes (imagine how they would be if math were actually required of them) and the pureblood wizarding world in general, which she says doesn't have "an ounce of logic".
A more straight version of this is Mad Eye Moody who hauls around a trunk primarily full of highly situational gear for fighting Dark Wizards, all this from a man who can see through walls (and the back of his own head). The fact that he still got jumped by a Death Eater in the fourth novel shows that in the wizarding world, being over-prepared is a necessity.
Aladavan, a sidhe wizard in Cerberon, always has something up his sleeve to get himself out of just about any situation, and he can quickly improvise a solution with whatever he happens to have on hand. Aladavan's wagon is packed full of useful things, including a folding table, a collection of magic wands, treasure chests, a library, and a spare wagon with a trunk full of emergency supplies. He stocks his satchel with any number of items that he anticipates might be handy at a moment's notice, including an enchanted sword, a bottle of wine, and a flaming timber.
Raoul Duke and Dr. Gonzo in Fear and Loathing in Las Vegas. "We had two bags of grass, seventy-five pellets of mescaline, five sheets of high-powered blotter acid, a salt shaker half-full of cocaine and a whole galaxy of multicolored uppers, downers, screamers, laughers... Also a quart of tequila, a quart of rum, a case of Budweiser, a pint of raw ether, and two dozen amyls..."
Terrifyingly, that passage comes from an actual segment of Hunter S. Thompson's journal, where he notes what he bought with the $300 in petty cash his editors gave him.
A character in one of Lawrence Block's "Ehrengraf" short stories places title character Martin Ehrengraf on retainer to defend him on the charge of murder. For a murder he intends to commit. Ehrengraf quips, "I wish all of my clients had as much foresight as you."
The Moomins series, by Finnish author Tove Jansson: Moomin's mother never parts from her handbag. When another character asks her what she is carrying that is so important, she replies: "Oh, stomach medicine and clean socks and steel wire and other things that might be useful". Also, her handbag frequently contains exactly the thing the family needs.
Clan Korval from the Liaden Universe. Due to a contractual oversight, they're legally still in charge of the planet of Liad should an enemy try to harm the citizens. The clan has been designed to be able to financially, mentally, and physically able to fight at any given moment. Complete with Time for Plan B emergency planning.
This is the whole basis of Neil Strauss's new book Emergency in which he details how he learned to start worrying and become crazy prepared.
In A Deepness in the Sky by Vernor Vinge, Pham Nuwen is crazy prepared. He's been preparing for hundreds if not thousands of years, collecting the most advanced technology from all over the galaxy and disguising it as innocuous materiel. He's learned and created countless secret programs and backdoors on the computers. All of Pham Nuwen's toys are standard equipment on Queng Ho ships, yet nobody else knows about them. Everybody is, although not to the same extent. In A Fire Upon the Deep, a children's toy computer, explained as being outdated but hung onto for sentimental purposes (it was shaped like a stuffed rabbit) includes as a standard feature 'uplift protocols' to allow any tech level short of flint and bone knapping stone age to raise the technology to build a subspare radio capable of reaching civilization to call for rescue.
Nakor in The Riftwar Cycle is crazy prepared, he can access a table full of useful items he has already assembled in a sealed cave through a rift in his seemingly empty rucksack including a royal Keshian falcon, long thought extinct, and a near endless supply of oranges through a separate rift to a fruit merchant's shop! Nakor is a fragment of a god, so a little foreknowledge probably helps
After falling into seawater we find out that the rift goes both ways, and that the fruit merchant will probably have at least one ruined barrel of fruit, after which the rift instead starts to produce apples.
In Dale Brown novels, Sky Masters aircraft come with the equipment and code necessary to mount Russian weapons just in case their crews ever need to use them, as noted in Wings of Fire.
In the Redwall book Rakkety Tam, just before the fight with Gulo, Tam sharpens the edge of his shield. During the fight, the shield is torn from his arm and embeds itself edge-on in the ground. Later on, Gulo is thrown into the air, and lands just right for the protruding shield-edge to decapitate him.
Rufo, from Robert Heinlein's Glory Road, carries a TARDIS-like backpack that, once removed from Rufo's back and unfolded (a process requiring several minutes of time and square meters of space) contains anything and everything that the protagonists might need on their mission. However, as his boss, Star, explains to Oscar (the first-person-narrator and protagonist), while the backpack damps out apparent weight enough to allow the wearer to lift it, its still got enormous mass and is thus very expensive to maintain and transport. Further, it has to be completely unfolded before they can get at anything they might need, making the thing less useful in the heat of battle or the cramped confines of a cave than Oscar might have liked.
This is parodied in The Hitchhiker's Guide to the Galaxy, with the towel. If you have your towel with you, everyone automatically assumes you are prepared for anything and will thus be happy to lend you anything you may have misplaced (food, money, spacesuits, etc).
Cookie from Nation, with his floating coffin containing everything a sailor lost at sea might need to survive.
Madame Ahnzhelyk from the Safehold series is remarked as planning ahead with a vengeance when it comes to her efforts to reform (and later subvert) the Church of God Awaiting. This is brought int full prominence in the fourth book A Mighty Fortress where plans she set up years ago (even before the current antagonist ever came into power) are used to evacuate as many victims of an upcoming Inquisition purge as humanly possible. Her efforts secure the escape of about a tenth of the intended victims, which include the families of prominent vicars and an archbishop.
The Church of God Awaiting's creators could be seen as this. As noted in A Mighty Fortress, because the Church was started as a Path of Inspiration to enforce Medieval Stasis, but Safehold was still a terraformed planet not originally meant for humans, the "Archangels" had to come up with divine or miraculous explanations for every possible known phenomenon known to man so people wouldn't go and ask "Why does X happen?" They managed it for close to a millennium before it started coming apart.
Decades before the main plot, while he was still Crown Prince of Corisande, Hektor Daikyn did the unthinkable and planted a double-agent within the Inquisition. While not intended for it, this act ultimately secured the successful rescue and Heel-Face Turn of his spymaster, his daughter and his younger son well after his own death.
Taken to a serious level in David Eddings's Malloreon series. Although not properly revealed until the final book, The Dark (and its agents) showed an unreal amount of advance planning for its conflict with the series' protagonists: always possessing a fallback plan whenever something didn't work. It is eventually revealed to be part of its fundamental mentality: the idea of a predetermined perfection. The Light is no slouch either...it has a tendency to place knowledge in people's minds or has them do something so that they'll remember about it hundreds of years later when they need it. Also, twice in Belgarath the Sorcerer, it altered weather patterns in order to give favorable odds to the Child of Light, the more extreme example being making it rain near-continually for twenty-five years...all to create a storm in a specific place that buried an unfriendly army under several feet of snow.
Jack West Jr. and his team in his series written by Matthew Reilly. Their farm in Australia gets attacked by paratroopers equipped with jeeps. They escape by driving through a bridge booby trapped with wheel puncturing spikes, into a river over a concealed concrete ford, into a 747 JUMBO JET hidden in the hillside and release a giant anti-aircraft bouncing bomb to take out 2 fighter jets. Crazy Prepared just doesn't come close.
In Harry Turtledove's Worldwar series, the Race arrives to Earth expecting a Curb-Stomp Battle against a bunch of Medieval knights. While what they find definitely shocks them (they arrive in the middle of World War II), they still give humans a hard time, as their military technology is decades (in our understanding) beyond what humans have. It could be understood that they brought tanks, jet fighters, helicopters, and machineguns to quickly subdue the local population with a display of awesome weaponry. However, there is no justification for them bringing dozens of nukes to fight a bunch of primitives, especially since they are doing everything they can to preserve the planet for colonization. Unusually for this trope, the nukes they bring don't do much to help the lizards, as humans haven't advanced yet to the point where EMP is harmful to their technology (the pulse only fries integrated circuits not vacuum tubes). Their nuking of Berlin and Washington only serves to piss off the locals. In fact, the lizard nukes end up helping humans, as they manage to obtain some radioactive material from the lizards and interrogate several of them in order to finish their own atomic bombs ahead of schedule.
Master Miller was shown to be this in the Novelization for Metal Gear Solid before he got offed. Although he had a main arsenal within the house, he also kept various weapons in each and every room in case someone managed to somehow infiltrate his house. However, it didn't save him from the gas.
In his book The Bad Book Club, Robin Ince talks about The Correct Guide to Letter Writing, which contains over 500 different letter templates. They start off sane enough with 'From a commercial traveller, suggesting special terms' but gradually get more crazily specific ('Accepting an invitation from a Gentlemen to Lunch at a Restaurant' is different from 'Accepting an invitation from a Gentleman to a Dinner and Theatre Party' apparently).
In the Belisarius Series, Valentinian knows everything about every possible situation in combat that might come up. He even trains a prince to be able to fight with a shovel in case he finds himself without a sword.
In Reamde by Neal Stephenson, the Chinese hacker group have spent some time devising a plan for escaping a zombie invasion, on the grounds that this is far more likely than a police raid. This turns out to be unexpectedly useful when the plot starts happening to them.
Rod averts the trope on his sister's advice, taking only a knife, pack vest, and rations on his off-world survival test. Deacon Matson even asks why he didn't arrive with camping equipment and popular outdoor gadgets like the other students.
Matson subverts the trope during the final inspection as students are expected to be prepared for any reasonable survival circumstances. Any student without cold weather gear and risking Exposed to the Elements fails automatically, despite Matson knowing they wouldn't need it for this test. Conversely, a few students prepare for vacuum or toxic environments and Matson fails them for bringing pressurized space suits: environments lethal to humans aren't a reasonable test parameter, at least without explicit warning of conditions.
The Host gives us Melanie's relatives, but especially Jeb - he completely overhauls a cave system to make it inhabitable, solely because he thought he'd need an Elaborate Underground Base someday.
Valentinian in the Belisarius Series. When he has to teach a prince how to fight, he even teaches him how to fight with a spade; even a prince might need to.
Imp Sec in Vorkosigan Saga embodies this trope, notably in the headquarters whose security is obsessively detailed and redundant including compartmentalization and internal life support that reminds Miles of a spaceship plus refusing to allow building across the street to ensure a clear field of fire.
Few people are better prepared than Jeeves, who in addition to knowing the exact social standing of every relationship in the British aristocracy, has a working knowledge of foreign language, psychology, fashion, economic theory (he can completely explain communist theory, despite being completely opposed to it), taxonomy (he refers to animals by their scientific names), and so on, and does it all with such cool implacability he practically qualifies more as a Do-Anything Robot.
The main protagonist from Black Tide Rising is a former special forces soldier with some family and friends in high places to watch out for potential problems. To discuss them (a wide range of possible disasters), he and his friends/family have enough plans for different apocalyptic scenarios that they have a codefor every single one of them.