SyntaxBoom

This is is going to be the start of a list of useful links to game libraries and game render engines. If anyone adds some gems, then they will be added to this post, so people don't have to go through every post.

NOTE: Many of these linked sites have not been checked for what contents they offer.
If they don't appear to be what is advertised, or look suspicious. Then PM an administrator so they can be removed.
So use at your own risk.

For a list of game art and texture libraries. See here (https://www.syntaxboom.com/forum/index.php?topic=26.0).
For a list of music and sound effects libraries. See here (https://www.syntaxboom.com/forum/index.php?topic=27.0).
For a list of programming languages and tools. See here (https://www.syntaxboom.com/forum/index.php?topic=28.0).


Game Libraries and Game Render Engines
3D/2D
Unreal Engine (https://www.unrealengine.com/en-US)
Unity (https://unity.com/)
Godot (https://godotengine.org/)
GDevelop (https://gdevelop.io/)
Phaser (https://phaser.io/)
Stride (https://www.stride3d.net/)
Construct (https://www.construct.net/en)
MonoGame (https://monogame.net/)
Defold (https://defold.com/)
Ogre (https://www.ogre3d.org/)
Hord3d (http://horde3d.org/) (Main link is not https, so direct link to github (https://github.com/horde3d/Horde3D) page)
O3DE (https://o3de.org/)
App Game Kit (AGK) (https://www.thegamecreators.com/)
jMonkeyEngine (https://jmonkeyengine.org/)
Babylon.js (https://www.babylonjs.com/)
C4 Engine (https://c4engine.com/)
ClanLib (https://github.com/sphair/ClanLib)
Click Team Fusion (https://www.clickteam.com/)
CryEngine (https://www.cryengine.com/)
Dagor Engine (https://github.com/GaijinEntertainment/DagorEngine)
Cube 2 Engine (http://sauerbraten.org/) (Main link is not https, so direct link to sourceforge page (https://sourceforge.net/projects/sauerbraten/))
Ursina Engine (https://www.ursinaengine.org/)
Unigine (https://unigine.com/) (A Python Library)
Wicked Engine (https://wickedengine.net/)
RayLib (https://www.raylib.com/)
bgfx (https://github.com/bkaradzic/bgfx)
libgdx (https://libgdx.com/)

2D Only
Adventure Game Studio (https://www.adventuregamestudio.co.uk/)
Cocos2D-x (https://www.cocos.com/en)
PyGame (https://www.pygame.org/news)
Pygame Community Edition (https://github.com/pygame-community/pygame-ce)
The Python Arcade Library (https://api.arcade.academy/en/stable/)
Ren'Py (https://www.renpy.org/)
pyxel (https://github.com/kitao/pyxel)

Low Level Development Libraries
SDL: Simple DirectMedia Layer (https://www.libsdl.org/)
GLFW (https://www.glfw.org/)
Free Pascal Meets SDL (https://www.freepascal-meets-sdl.net/)
Light Weight Java Game Library (https://www.lwjgl.org/)

Audio Development Libraries
OpenAL (https://www.openal.org/)
OpenAL-Soft (https://github.com/kcat/openal-soft)
SoLoud (https://solhsa.com/soloud/)
Juce (https://juce.com/)
FMod (https://www.fmod.com/)
Various (https://gist.github.com/tido64/f1177d85416a09e67147)

Physics Engines Libraries
Box 2D (https://box2d.org/)
Bullet 3 (https://github.com/bulletphysics/bullet3)
Newton Dynamics (https://newtondynamics.com/forum/newton.php)
Open Dynamics Engine (https://www.ode.org/)
NVIDIA PhysX (https://developer.nvidia.com/physx-sdk)
Project Chrono (https://projectchrono.org/)

Unigine Engine (https://unigine.com/)

Ursina engine (extremely well simplified Panda3D)

https://www.ursinaengine.org/