Remember Radio 4's "History of the World in 100 Objects"? The US fanzine Lofgeornost was inspired to suggest a History of the Future in 100 SF Objects – a great display for some World SF Convention.
There'd have to be a Time Machine (H.G. Wells or the Tardis?) and an iconic Spaceship (2001?) or Starship (Star Trek?) docking at a Space Station. Also in the Transport department: Flying Saucers, Flying Cars, Rockets, Moving Roadways (see Heinlein's "The Roads Must Roll"), Antigravity, Matter Transmitter, Jetpack/Gyropack, Warp Drive, Space Elevator and Stargate ... A.E. van Vogt, as you probably did not wish to know, wrote about stargates in 1942.
A Positronic Robot and its Three Laws are essential, plus a futuristic (and optionally Mad) Computer working as a Universal Translator or issuing helpful information like "???Redo from Start", "I'm sorry, Dave. I'm afraid I can't do that." or "Yes – NOW there is a God!"
The hugest exhibit hall is for Big Dumb Objects, including the Death Star, Larry Niven's Ringworld and the Hollow Earth (looks like Earth, but ...).
Conversely, one teensy portable display case holds many Nanobots, a bit of that useful Monomolecular Wire that slices through anything but especially fingers, a few Tachyons, the World-Ravaging Plague of your choice and the Incredible Shrinking Man.
For SF handguns, there are too many options. The traditional Blaster, Disintegrator and Stunner can become a single handy package: "Set phasers to Violate Prime Directive!" Larger ordnance includes Powered Armour, Mecha, Cybertanks like Keith Laumer's Bolo "continental siege units" and Doomsday Weapons – paging Doctor Strangelove ...
Tomorrow's books: everything you could possibly need to know is in the Encyclopedia Galactica from Isaac Asimov's Foundation series, and for everything else there's the Hitchhiker's Guide.
Future physical fitness is encouraged by Bug-Eyed Monsters and other things from which to run away very fast indeed: Martian Tripod, Triffid, Id Monster, Blob, Alien Grey, Dalek, Sandworm and H.R. Giger. When thoroughly exercised, take a break to enjoy some Food Pills.
Other vital technological gimmicks are Stasis Fields, Cyborgs, Miniaturizers (enjoy a bacteria-hunting safari!) and Identity Transfer gadgets to allow mind tourism as in Robert Sheckley's Mindswap. Justice is ensured by infallible Lie Detectors and total surveillance via Spy-Rays, while magical new Power Sources – tapping, for example, the zero-point energy of space itself – replace fossil fuels at last and provide a fast track to Utopia. Or Dystopia.
There'd be a wide range of entertainment, from the Holodeck and another 57 varieties of Virtual Reality to panes of Bob Shaw's Slow Glass, showing idyllic country scenes from years ago when the light first entered the glass. Avoiding the boring old speed-of-light regulations, bad news will arrive instantaneously by Ansible. Or Ultrawave, or Dirac Communicator. You can even get the news before it happens by investing in a Time Radio.
Laboratory supplies: Green Kryptonite of course, Cavorite, Antimatter (carefully packaged) and Unobtainium. One of the many Drugs that prolong life – perhaps Frank Herbert's Spice (see Sandworm above) or Cordwainer Smith's Stroon, a by-product of gigantic diseased sheep.
In fashion, Spacesuits with Bubble Helmets have a retro charm; and an important survival tip is to avoid wearing Red Shirts.
All visitors to the exhibition will have a chance to guess the nature and purpose of the Utterly Incomprehensible Alien Artefact. There may be an utterly incomprehensible prize.
Catering to the needs of future plotting, we'd need many Clichés, Stereotypes and Infodumps, at least one McGuffin, and a reliable Deus Ex Machina. Since these things tend to be a bit intangible, they can share the large glass case already containing an Invisible Force Field, a Cloaking Device, the Fourth Dimension, and the Pitiless Vacuum of Space.
Oops. The end of the page already and we're still a long way short of a hundred. Must try harder.
You guessed it: David Langford wrote or expanded entries on most of these things for the SF Encyclopedia.