Lately I made some freetime pixel art trials called #8to64. That means you start by 8x8 canvas and create 16, 32, and 64 px advancement of the concept you do. I'm a beginner on this, but sometimes it's great fun to work with pixels instead of 3D models. There are beautiful examples all over the facebook and instagram with #8to64 hastag.
I created these by using an app called Pixel Studio on my android tablet. Hope you like it.