- Unity You can't beat free. The Unity game engine can build just about any type of game including 3D, 2D, mobile, PC, and multiplayer games. It's a very popular game engine and has millions of users.
- Unreal Engine 4 Unreal Engine 4 is another free to use game engine that allows you to produce high-quality 3D games. Just like Unity, they support almost every type of platform to publish your game to.
- Game Maker 2 Mainly used to make 2D games but also has support for 3D games. One big feature is that it lets you build the 2D assets right in the editor. It's a user friendly game engine and is easy to get started with.
- RPG Maker A popular game engine used to make RPG games. It can make other genres of games but its main focus is with RPG games. It does cost money to use this game engine but it has a very supportive community.
- Love 2D A free and open source 2D game engine that is great for beginners. This game engine is user friendly and uses the programming language Lua. It has an active community.
The community is strong and the amount of tutorials on the engine is abundant. There is also an asset store where you can import pre-built content such as 3D art, scripting tools, and AI. Most of the asset store content is paid but there are some very useful free asset store items as well.
One of the free asset store tools I would recommend is ProGrid and ProBuilder. With ProGrid it snaps the placement of 3D models. It can be a major time saver when building a 3D game world. With ProBuilder you can actually build 3D models right inside of Unity. ProBuilder does take some time to learn but once you know how to use it, it is a very powerful tool to use.
They seem to have a focus on VR, AR, and mobile games. The editor comes with a suite of features to build your 3D game. It also has a supportive community.
It also has its own marketplace to sell your game. It does have a free trial but does cost money to use long term.
It also has a WYSIWYG editor so it can be easy to get started although more complex games can take a learning curve to build.