Single Phlebotinum Limit

In some fictional worlds, all the crazy (and mundane) technology is powered by a single kind of Applied Phlebotinum, often even the very simplest things that otherwise would be very simple to do, such as electricity or even fire.

Related to, but not quite the same as Minovsky Physics (In that it might not be heavily explained, and particles that follow Minovsky Physics may be joined by other Phlebotinum) and Green Rocks (which vaguely defined enough to be used for everything, aren't necessarily always used as such.) A Phlebotinum Muncher takes this to its logical conclusion by feeding on the phlebotinum.

Steampunk and other *punks tend to be like this to a greater or lesser degree, Phlebotinum Du Jour based works as often as not.

Subtrope of The "Unicorn In The Garden" Rule.

Anime and Manga

 * Giant Robo: The Shizuma Drive (Explained in that it's pretty much free unlimited cheap power and it's totally scalable, subverted in that it shows you shouldn't put all your eggs in one Phlebasket.)
 * Code Geass: Sakuradite, although there are other forces at work, every piece of non-real-life technology is Sakuradite-based.
 * As well as, apparently, all the power plants; the Gefjun Disturber is explicitly stated to affect only Sakuradite-based tech, and when used to cripple Tokyo's defences in the Second Battle for Tokyo knocks out every electrically-powered device in the city.
 * Steam, in Sakura Taisen. The manga included a reference to "steam mobile phones."

Comic Books

 * Warriors of Plasm is set in an alien world where absolutely everything is based on Biological Technology. Justified in that their world itself is a giant, squishy living organism.

Literature

 * Discworld has Narritivium. Everything traces back to it; justified by the fact that narritivium is literally story- so of course it causes everything, the Discworld is a series of books!
 * The Eastern Empire in Mercedes Lackey's Valdemar books has become so dependent on magic for basic needs like heating that it nearly collapses when magic becomes unreliable.

Live-Action TV

 * Everything in the Stargate Verse runs on Naquadah or Naquadriah (which is really just a more potent variety of the former.) The gates are made out of it, bombs, the starships run on it, it's the core element in the Replicators... If what you want to do can't be done with Naquadriah, the you don't have enough of it. Stargate Universe kicks off the plot by using a planet which has its entire core made up of Naquadriah to reach the Destiny.

Newspaper Comics

 * While it didn't run everything, an awful lot of the heroes' technology in Buck Rogers was based on the synthetic antigravity substance "inertron." This is really a perfectly justifiable application of Niven's Law—if an antigravity substance existed, it would be incredibly useful; once the stuff was introduced into the series's continuity, it would be odd if it didn't start appearing in all kinds of machinery.

Tabletop Games

 * Deadlands: Ghost rock.
 * Mostly, but there are other minor Phlebotinums; ghost rock isn't responsible for the powers of hucksters, shamans, and blessed, for example.
 * Shock Social Science Fiction does this, recommending only one Shock per session.

Video Games

 * Skies of Arcadia: Moon Stones. They even make liqour Loqua out of it.
 * Mass Effect: Element Zero.
 * Mega Man Battle Network: The Internet.
 * Zone of the Enders: Metatron, powering everything from repair, to making prosthetic hands out of it, to being the secret behind advanced AI's.
 * Valkyria Chronicles: Ragnite.
 * The tititular Elebits.
 * Iji has nanomachines.
 * As does Metal Gear.
 * X-COM: Elerium
 * Final Fantasy VII: Mako, which is actually the Lifestream, and all Materia is a condensed form thereof.
 * The Crystal Chronicles series has magicite, which is used for everything from making fires to purifying water. Kinda justified though, as it does warp reality.

Web Comics

 * Awkward Zombie, making fun of Mass Effect: everything is... mass effect! Except translation - that's magic.
 * And bureaucracy. "I'm pretty sure even mass effect can't explain a bureaucratic process getting instantaneous, tangible results."

Web Original

 * The substance known as "handwavium" from the collaborative writing project Fenspace basically "uplifts" ordinary technology into ultratech.

Western Animation

 * Storm Hawks: Crystals. They even have flavoring crystals for making food, including one that turns things into cheese.
 * Flavoring crystals? Like salt?
 * Bionicle: Protodermis in the Matoran Universe.
 * Pretty much everything in the Transformers Verse runs on Energon. The earliest Marvel Comics stories avert this, having them use a liquid fuel that can be derived from oil, but the writers quickly adopted energon from the TV series and never looked back.

Real Life

 * Truth in Television: back in the 1950s they thought everything in the future would be nuclear. Cars, planes, toasters, the water in your house. All improved thanks to the power of your friend, the atom!
 * ...but in actual reality, most everything seems to depend on oil :(
 * We're not in the future yet.
 * Not until we have flying cars and personal jetpacks. Also flying skateboards.
 * Wait...what?
 * Blake Snyder's Save the Cat book on screenwriting specifically advises authors to do this under his Double Mumbo Jumbo theory. According to him, if you try to make the audience buy two separate supramundane elements it stretches the film's credibility to the breaking point. He pointed out a flop like Signs which asked the audience to juggle a debate over whether or not God exists and one over whether or not evil space aliens exist.