Here we have my foray into GameBoy programming. I will mostly be using the WLA-DX assembler so the code snippets will follow that syntax. It shouldn't be too bad, however, for those that are using the probably more popular RGBDS assembler. I can understand their syntax just fine!
You can find most of my GameBoy code in my github repo. Figuring out how the gameboy system works but the Gameboy PanDoc makes it a whole lot easier. I also use a basic opcode summary when I need to look at the opcodes at a glance. Sometimes you need to know where everything is in the GameBoy Memory so I use a handy memory map. And finally for the last links, I have a link to the "Awesome List" for Gameboy development on Github which has all the other links you should need. It really lives up to it's name.
I have also uploaded a slightly modified version of Chris Antonellis' Gameboy Tile Data Generator here