Castle Game Engine - An open-source 3D/2D game engine for ObjectPascal.
Time4Learning - Time4Learning provides Online Education for PreK-12th Grade covering various subjects, including Math, Language Arts, Science, Social Studies, and many more.
Open 3D Engine - Open 3D Engine is an open-source 3D game development engine in real-time.
Homeschool Tracker - Homeschool Tracker is an online web app that enables thousands of people worldwide to track the hours and attendance of students, generate reports, manage copy and reschedule assignments, and more.
Godot Engine - Feature-packed 2D and 3D open source game engine.
Sonlight - Sonlight offers a complete Christian homeschool curriculum for PreK-12 that you can purchase for your kids.