Wear OS Center - Wear OS Center – Android Wear Apps, Games, and News is an all-in-one launcher for your smartwatch that delivers all your Android Wear apps and watches faces all in a single place.
InfiniLink - iOS Companion App for InfiniTime and the PineTime smartwatch
Wear OS by Google Smartwatch - Wear OS by Google Smartwatch (was Android Wear) is a powerful app that syncs your smartwatch and phone so you can get more 0ut of your watch.
Gadgetbridge - A free and cloudless replacement for your gadget vendors' closed source Android applications.
Amazfish - SailfishOS companion application for Huami Devices (such as Amazfit Bip, Cor, Mi Band 2/3 and GTS), PineTime InfiniTime and Bangle.js
wasp-os - Firmware for smart watches based on the nRF52 family of microcontrollers (including Pine64 PineTime)