In simple words, Unity3d is the world’s most popular game creation engine. It packages a ton of core features together and is flexible enough to make almost any game a designer can imagine. Unity started it’s path to glory with unrivaled cross-platform features and the engine is popular among both hobby developers and triple-A studios. The Unity3d game engine has most recently been used to create games like Pokemon Go, Hearthstone, Rimworld, Cuphead and many more.
While most often used for 3d games (hence the 3d in the name), Unity 3D also comes with lots of tools for 2D game development. Programmers have always been in love with this engine because of the C# scripting API and built-in Visual Studio integration.
Artists also enjoy Unity3d a lot because it contains a range of powerful animation tools that make it simple to create your own 3d cutscenes or build 2d animations from ground-up. Nearly anything can be animted in Unity (even without the use of additional Assets).
Finally, Unity3d features a free version so indie developers can release games made with the engine without actually paying for the software, as long as they earn less than $ 100,000 from their games (quite a benchmark to reach for a indie dev).
Computer Games and Mobile Games require decent art as well, and Fantasy Stockart is ideal to be used as icons, textures, backgrounds and decorations for those games.