Godot Engine - Feature-packed 2D and 3D open source game engine.
Twine - Twine is an open-source tool for telling interactive, nonlinear stories.
Unreal Engine - Unreal Engine 4 is a suite of integrated tools for game developers to design and build games, simulations, and visualizations.
RenPy - Ren'Py is a free and cross-platform visual novel engine that helps you use words, pictures, and...
Unity - The multiplatform game creation tools for everyone.
Quest - Quest lets you create sophisticated text-based games, without having to program.