iControlPad2 $62
Building a carputer or autonomous robot with a Raspberry Pi is cool but once you need to connect a keyboard, mouse, and other peripherals it starts to look a little clunky. The iControPad 2 is a vast improvement over lugging an old Dell keyboard and mouse around just to interact with a Raspberry Pi. It’s a small, battery-powered Bluetooth-enabled keyboard, gamepad, and mouse that is barely larger than a Raspberry Pi. Perfect for building a portable MAME machine, carputer, or just to have a really, really tiny keyboard around.

Edimax USB Wi-Fi Adapter $18
Currently one of the smallest USB wi-fi adapters, this little networking dongle plugs into the USB port of your Raspberry Pi and connects you to your wireless network at home, school, work, or your local hackerspace. Unlike a many other larger USB wi-fi adapters, this one is ready to roll with the drivers already packaged with most major Raspi Linux distributions. It’s also very, very cheap at under $10 from many retailers, making it a perfect stocking stuffer.

Arduino Prices vary depending on version
The Raspberry Pi is a wonderful tool that enables a lot of projects that need a lot of computing horsepower. It even has a few pins broken out that can be controlled by a short bit of Python code. Still, these IO pins aren’t 3.3 Volt tolerant and there’s only one PWM pin. The Arduino, after all these years, still provides a great bridge between the virtual world of the Linux desktop and Internet to physical devices. If you need to control several motors, LED, or servo from a Raspberry Pi, there’s still very few better ways of going about it than an Arduino.

Milled Aluminum Case $74.95
Every Pi needs a case, so when it comes time to protect your Pi from the cold reality of dropping it on the ground, it’s time to either go big or go home. This case is milled out of a solid block of aircraft-grade aluminum and should provide sufficient protection from small children, playful dogs, or a full-scale nuclear exchange between nations. It’s a bit on the pricey side at $75, but it’s absolutely gorgeous especially with the engraved Raspberry Pi logo.

MAME Buttons and Joysticks $130-$200
A classic project for makers the world over is to take an old computer and monitor, connect a few buttons, and build a MAME cabinet. It’s an old-school arcade cabinet able to emulate classics such as Galaga, Pac-Man, Rampage, and Street Fighter. The Raspberry Pi is more than capable of running a derivation of the MAME emulator, so the only thing standing between a Raspberry Pi owner and their own personal arcade is a few buttons and joysticks.

USB Battery Pack $36
The Raspberry Pi is powered by a Micro USB port, just like nearly every cell phone charger on the planet. A ton of manufacturers realized a portable battery pack able to charge a phone is a good thing to have and they have put out quite a few lithium-ion USB battery packs able to charge a cell phone, tablet, or power a Raspberry Pi. If you or someone you know is looking to take a Raspberry Pi off the grid, these battery packs provide all the hardware and equipment necessary to make that idea a reality.

Motorola Lapdock Discontinued. Available used
The Motorola Lapdock was an odd experiment intended to turn a few select smartphones such as the Motorola ATRIX 2, PHOTON, and DROID BIONIC into full-fledged Android laptops. Although originally designed for phones, it’s possible to collect a few USB and HDMI cables and use the Lapdock with a Raspberry Pi. The Lapdock has a touchpad, keyboard, 10.1-inch monitor and on-board battery, allowing anyone to turn a Pi into a laptop. Motorola discontinued the Lapdock, but luckily you can pick them up for a pittance on eBay or Amazon.

Raspbery Pi T-Shirt $24
If you’re buying for a Raspberry Pi aficionado who already has everything else on this list, how about getting him an official Raspberry Pi T-shirt directly from the Raspberry Pi foundation. As part of the perfect wardrobe for heading over to the local hackerspace or Linux user group meeting, these shirts tell the world you’re loving the Raspberry Pi without having to say anything. For a subtler tact, there’s also Adafruit’s Raspberry Pi Skill Badge, $3.95, a two-inch high iron-on badge that is perfect for a jacket, overalls, or work clothes.