@point-of-sale/webserial-receipt-printer
This is an library that allows you to print to a receipt printer using WebSerial. This can either be a printer connected using a serial port, or a printer connected in any other way where the driver sets up a virtual serial port for compatiblitity reasons
@tomneutens/serial_monitor
A web based serial monitor for communicating with serial devices (like Arduino). The library is based on native web components and uses the WebSerial API to communicate with the external device.