Quad GPIO Expander for Raspberry Pi Pico - Seeed Studio | Mouser
USB digital GPIO I/O extender
MCP23008 MCP23017 24-Channel Digital Input/Output with I2C Interface - store.ncd.io
USB digital GPIO I/O extender
Raspberry Pi Pico Dual Gpio Expander Four Sets Of Male Headers Usb Power Connector Expansion Board For Rpi Pico - Demo Board Accessories - AliExpress
Sinelec Technologies
128 Channel USB GPIO Module With Analog Inputs | Numato Lab
MCP23017 - i2c 16 input/output port expander : ID 732 : $6.95 : Adafruit Industries, Unique & fun DIY electronics and kits
Adafruit GPIO Expander Bonnet - 16 Additional I/O over I2C | The Pi Hut
Use Mini PC / Minix (Neo Z83-4) for Home Assistant - what extra hardware for Zigbee and IOs? - #12 by Marc_Sway - Hardware - Home Assistant Community
8 Channel USB GPIO Module With Analog Inputs | Numato Lab
Amazon.com: Waveshare Quad GPIO Expander for Raspberry Pi Pico Four Sets of Male Headers for Connecting More Expansion Modules with USB Power Input Connector : Electronics
Amazon.com: XICOOLEE Pico Expansion Plus GPIO Expander for Raspberry Pi Pico, Two Sets of External Expansion Pins 2x20PIN, Pico Dual Expander : Electronics
16 Channel USB GPIO Module With Analog Inputs | Numato Lab
16 Channel USB GPIO Module - 16-channel IO expander with USB communication - Kamami on-line store
Computer Office Dual Gpio Expander Module Replacement Usb Power Connector Extension Board For Raspberry Pi Pico Interface - Demo Board Accessories - AliExpress