The SYGBox by SaveYourGames is a 3D-printed hitbox that lets you choose button and cable colors as well as the PCB.
As expected, the VM6 by ASI is a class act and can be ordered in fightstick or mixbox formats with custom art.
This all-button controller that you can also get in a black color to hide the components is a customizable beauty.
The Brook Agon Arcade Stick Collection provides you two different arcade sticks to choose from with plenty of customization opportunities.
The OkiBoard is a leverless controller that adds to the arsenal of controllers coming from the United Kingdom.
The FightBox B1 is an all-buttons controller that prides itself for being ultra thin.
ASI hit a homerun with this highly customizable case that can also be ordered preassembled. A mixbox edition is available too.
This handmade beauty by 2nd Stage Creations is fairly customizable, with the star component probably being the wood.