Raspberry Pi: The Raspberry Pi is a popular open source single-board computer that can be used for a variety of projects, including media centers, game consoles, and robotics.

Arduino: Arduino is an open source micro-controller platform that can be used for a wide range of projects, including robotics, home automation, and electronic art.

Open Compute Project: The Open Compute Project is an open source hardware initiative that aims to design and enable the delivery of the most efficient server, storage, and data center hardware designs for scalable computing.

Open Source Robotics: There are a variety of open source robotics platforms available, including the Robot Operating System (ROS), which is a collection of software frameworks for building robot applications.

Open Source Drones: There are a variety of open source drone platforms available, including the ArduPilot project, which is a suite of software that allows for autonomous flight control of drones.

ESP32

NodeMCU