+ https://www.circuitsathome.com/products-page/arduino-shields/usb-host-shield-2-0-for-arduino-assembled/
+
+Other compatible boards like Arduino's Shield will also work well but I think Sparkfun's needs to be modified.
+
+ http://arduino.cc/en/Main/ArduinoUSBHostShield
+ https://www.sparkfun.com/products/9947
+
+Also Pro Micro 3.3V(not Mini) or Teensy with mini host shield will work with some fixes on signal/power routing.
+
+ https://www.circuitsathome.com/products-page/arduino-shields/usb-host-shield-for-arduino-pro-mini
+ https://www.sparkfun.com/products/12587
+ https://www.pjrc.com/teensy/td_libs_USBHostShield.html