Fighting games like Virtua Fighter, Tekken or Street Fighter originated at the arcades and have traditionally been played on cabinets with heavy duty joysticks and buttons. Even though they're mostly played on consoles and PCs these days, many players use arcade sticks modeled after the arcade cabinets, either because they consider them superior to controllers or simply because they enjoy their old school look and feel.
Arcade stick parts like buttons and joysticks can be bought separately so it's fairly easy to make your own stick. All that's needed is some kind of a box and a microcontroller that will read the state of the buttons and send the appropriate inputs to the PC or console. Not suprisingly, there's a thriving DIY community of fightstick makers.
I designed a few arcade stick cases meant to be 3D printed. The ones shown below all use an Arduino Pro Micro as the brains, running this firmware, compatible with PC and PlayStation 3. If you like any of them and want to try making your own, I've posted all the 3D-printable models on Printables, along with more pictures and details on how to make them.
The first one uses the most classic layout, with a Sanwa JLF joystick, 30 mm action buttons and 24 mm option buttons at the back. I made versions with 6 and 8 actions buttons.
The traditional appeal of arcade sticks doesn't mean that things are standing still. Some new stick layouts have emerged over the years, the most popular of them probably being the hitbox layout, which ditches the actual joystick and instead uses four buttons for the direction inputs. The large button at the bottom is the jump button and it's meant to be operated by either your left or right thumb. This layout seems best suited for 2D games like Street Fighter. You can see my take on this control scheme below.
Another layout that uses buttons instead of the joystick is the mixbox layout. It uses keyboard keys in a more familiar WASD shape for the direction inputs. In my opinion it's better for 3D fighters like Virtua Fighter and Tekken than the hitbox layout. Here's my version.
In addition to new stick layouts, people have also started putting alternative parts in their sticks. One move that's obvious in retrospect is to try using mechanical keyboard switches instead of the traditional arcade buttons. There are many different keyboard switches to choose from and they also allow the fightstick case to be much slimmer. Here's my attempt at a hitbox-layout controller that uses Kailh low profile keyboard switches and is just 14 mm thick (I call it the Slimbox).
Similarly, here's a mixbox-layout version of the same idea (Slimbox M).