Inspiration for this post was a similar post: chess for GameBoy, which tried to design chess pieces for a very limited display. I realized I've done the same in the past so I am posting my chess set as well. There are two versions: one with color, one in black and white (1bit). With such limitations it is surprisingly hard to make a set that's actually usable in which the pieces look both nice and quickly recognizable, but after playing with these sets I got used to to them and felt quite comfortable (a chess game I made with this can be found here). I don't believe you can go much smaller in designing chess pieces, each piece is 8x8 pixels, so you can store each piece picture in a single 64bit integer.