16 pixels by 16 pixels is a common resolution for assets matching a low-res pixel art aesthetic. Although the assets may not be specifically 16x16, they are designed to work in a graphical setting where objects are around that size.
Games made for LOWREZJAM. A game jam where you make a game with a resolution of 64x64 pixels using whatever programming platform you'd like, with as few or as many colors as you'd like, with any fidelity of sound you'd like, and 2D or 3D graphics!
