The Adafruit Grove and Stemma QT FeatherWing for all Feathers allows folks to use many Grove devices with Feather boards! It fits nicely on top and has 3x Analog/Digital connectors, 1x UART connector and 2x I2C connectors. Not a ton, but enough to get many small projects going! We even managed to fit a vertical Stemma QT port on the end for another I2C connection.
Grove is a plug-and-play system from Seeed that features a 4-pin 2mm pitch connector (that is not JST PH). One thing to note is that the same connector is used for analogue, digital, I2C, PWM, or UART: power, ground and two signals. So before plugging in a Grove sensor please make sure that you have the right 'matching' port: UART Groves should only go into the UART port. I2C Groves go only into the I2C ports. Also, not every Feather has 6 Analog inputs, for example, the RP2040 Feathers have only 4, or have hardwarehttps://theihuty.shop/introducing-adafruit-stemma-qt/seeed-studio-grove UART that is available for peripherals, like the ESP8266 - so be aware of the underlying Feather boards' capabilities!
Comes with an assembled FeatherWing and two pieces of 16-pin header. Some light soldering is required to attach the header so it can be plugged into your Feather or doubler.