Project Spark is described as 'is “where players create and creators play”' and is an app in the Development category. There are more than 25 alternatives to Project Spark for a variety of platforms, including Windows, Mac, Linux, Online / Web-based and Oculus Rift. The best alternative is Godot Engine, which is both free and Open Source. Other great apps like Project Spark are Unity (Free Personal), Unreal Engine (Free), Wick Editor (Free, Open Source) and CRYENGINE (Free Personal).
Godot is a fully featured, open source, MIT licensed game engine. It focuses on having great tools, and a visual oriented workflow that can export to PC, Mobile and Web platforms. It is a cross-platform 2D and 3D game engine and game development IDE.
Unreal Engine is a professional suite of tools and technologies used for building high-quality games across a range of platforms. Unreal Engine’s rendering architecture enables developers to achieve stunning visuals and also scale elegantly to lower-end systems.
The Wick Editor is a free and open-source tool for creating games, animations, and everything in-between. It's designed to be the most accessible tool for creating multimedia projects on the web. Your creations can run on any device with a web browser - that means mobile too.
Cocos Creator is a complete package of game development tools and workflow, including a game engine (based on Cocos2d-x), resource management, scene editing, game preview, debug and publish one project to multiple platforms.
Open 3D Engine (O3DE) is an Apache 2.0-licensed multi-platform 3D engine that enables developers and content creators to build AAA games, cinema-quality 3D worlds, and high-fidelity simulations without any fees or commercial obligations.