Stencyl
2D game engine written in Haxe, with a block based visual scripting system inspired by Scratch
 
Echo Engine
Echo is a game engine which uses many industry-standards for game development
 
Cocos2D-X
A multi-platform framework for building 2d games, interactive books, demos and other graphical applications
 
Superpowers
Free and opensource 2D+3D game making for indies
 
PX8
Lightweight fantasy console for making retro inspired games
 
Buildbox
An engine that allows anyone to design, build, and publish amazing 3D and 2D games
 
Clickteam Fusion 2.5
Battle tested 2D game engine with an accessible visual scripting system
  Easy RPG
EasyRPG is a community project to create a free, open source, role playing game creation tool, compatible with RPG Maker 2000/2003 games.
  Esenthel
"Esenthel" is a mix of words: Essential and Essence, with a touch of magic
 
Evergine
The graphics development engine for business and industry
  Macroquad
A simple and easy to use game library for Rust programming language, heavily inspired by raylib.
 
Next2D
An engine that provides a WebGL 2D rendering, a web authoring tool for animation production, and a framework to support team development
  Quadplay
A fantasy console by Shmuel and Morgan at CasualEffects for creating and playing retro-style video games on any device.
  RavEngine
A C++20 cross-platform game framework, with emphasis on addressing pain points in existing game engines
 
RealityKit
Apple's first-party 3D engine
  Roblox Studio
Roblox Studio is an all-in-one IDE that lets you create experiences that run on Roblox. It lets you reach millions of users using the Roblox app on console, desktop, and mobile devices.
  seccia.dev
A point-and-click adventure game engine designed with non-programmers in mind and solely for that genre
 
SpriteKit
A framework for 2D game development provided by Apple
  Sritewidget
SpriteWidget is a toolkit for building complex, high performance animations and 2D games with Flutter
  Unbound
Unbound is a new engine built around creating with SDF shapes. Quickly bring your ideas to life with powerful game-making tools that are enjoyable for experts and newcomers alike.