The Teensy is a complete USB-based microcontroller development system, in a very small footprint that is compatible with the Arduino ecosystem.
Teensy products are manufactured by PJRC.
Teensy LC with Header Pins
Teensy Audio Adaptor Board for Teensy 3.X (Rev. C)
Teensy Audio Adapter Board for Teensy 4.0 (Rev D)
OctoWS2811 Adapter for Teensy (Controller for Neopixels/WS2811 LEDs)
Teensy 3.x Feather Adapter
USB Host Cable For Teensy 3.6 or 4.1
Ethernet Kit for Teensy 4.1
PSRAM Chip for Teensy 4.1
Teensy Header Kit
Break Away Headers - Straight