Game centers in Japan are known mostly for toys, like figures and plushies. Those do tend to dominate their stock, and are unfailingly popular. If you look past the toys, however, you’ll find a surprising number of useful items.
Useful items I’ve seen but not won (due to difficulty or lack of interest) include mundane things like pens, erasers, and lint rollers (or their larger counterparts). More unusual things I’ve seen include digital clocks, stools, and even those swivel skateboards.
Unsurprisingly, I’ve managed to win many types of useful things. It’d be easier to just make a list:
Caps, t-shirts, sweat shorts, scarves, hooded sweatjackets, backpacks, duffel bags, messenger bags, tote bags, wristwatches, pocket watches, long wallets, blankets, sheets, pillows, cushions, hand towels, bath towels, battery chargers (one with a speaker and two with lights), MP3/MP4 players, headphones, earphones.
I’ve also acquired other oddities, including a ninja-to umbrella, two Bluetooth speakers (one of which can play MP3s from a microSD), a clip-on phone-camera lens enhancer, a giant flashlight, a multipurpose electric screwdriver, a sleeping bag, a rolling suitcase, and a Coke-branded metal tumbler.
Because space in Japan is such a premium, I tend to only go for useful items these days. And things I can wear on my head, but that’s another story.