I'm still impressed by the power in the diminutive Raspberry Pi, a flexible hobbyist PC that can be used to run emulators or a home server or other creative projects. But the Raspberry Pi looks practically gargantuan next to the Pico PI225-GK, which I checked out at Zotac's booth at Computex 2018. This is actually the second generation of the mini PC, which is about the dimensions of a half dozen credit cards stacked together. It's a PC that could easily fit inside a money clip.
Of course, small computers are practically everywhere these days, in our refrigerators and gaming mice and wherever else we think to put them. But I was impressed by how much of a genuine PC the Pico is. It runs Windows 10, has two USB-C ports for connecting accessories and outputting video. It's clocked at 1.1 GHz with a dual-core Intel N4000 processor, which can turbo up to 2.6 GHz. There's 4GB of RAM in here. 32GB of memory. Wi-Fi, Bluetooth, and a card reader are built in, and it runs off micro-USB for power.
The Intel UHD 600 graphics built into the CPU are not built for gaming; this system is really envisioned as the driver for advertising displays. But if you don't mind playing lightweight games, or 3D games from the early 2000s, you really could have a PC that fits in your pocket. I mean, it'll definitely run Doom.