BitScope BS10U - Fully Featured USB Mixed Signal Oscilloscope for Rasp — Pi Supply
Beagle USB 12 - Low/Full Speed USB Protocol Analyzer : ID 708 : $495.00 : Adafruit Industries, Unique & fun DIY electronics and kits
Amazon.com: ViewTool Ginkgo USB to CAN Bus Adapter Support Windows/Linux/Mac/Android/Raspberry Pi, USB-CAN Connector/Analyzer Compatible with I2C/SPI/UART/ADC/DAC/GPIO : Electronics