Game Design Patterns

I'm using the Unity3D engine for a couple of years now, and I also developed some apps for the Android operating system. and I want to sharpen my fundamentals in writing code, especially after I see that Unity and other engines makes me Drag & Drop objects, or write just some couple of classes and managers that all recognize and share each other functions and code.

I feel like I am degenerated, today's Game Engines (and other software engines) makes me just use OOP in the most simplest and "ugly" way, and I want something that will make me write/design code and think. using Interfaces, Commands, Singletons, and etc. I want to see UML charts and to feel like I am actually planning in a wise manner my game, and not just writing public functions.

I downloaded some sample projects, and I see aesthetically written code, which I want to create also, and I want to know how write that way. so I'm looking for Game Design Pattern books, or eBooks that could help me be a better game designer and developer as I work with the Unity Engine.

I did hear about the Gangs of Four, which is as far as I understand the corner stone for game designing, however, I feel like I need something which is more specific to today's way of work, with the simplified Game Engines like Unreal SDK, Cryengine, and Unity3D.

I also found this nice eBook, that a friend and I recommend Game Design Revisited, that sums up a lot of the stuff I used as a programmer as I studied Software Engineering, and how to actually implement them in Game Design.

Any help would be kindly appreciated.

EDITED: since my request wasn't clear enough, I'm looking for good tutorials for game designing, books, eBooks, and so on, anything that you can share here.