Pixel Art Normal Maps
If you’re wanting to make a 3D game with pixel art textures, ie. Minecraft-style, normal maps are an easy way to add depth and shading. Normal maps are a way of using a 2D texture to simulate depth and detail. Adding a normal map to your pixel art textures makes it look like the 2D texture is 3D with how the light bounces off of it.
A great tutorial for this technique is HERE.