You need 20 sprites of what? Fish, a pony, undead pirates, grass, water, banana trees or a black void? You gotta be more specific, are quite a lot of places on the web with free sprites you can pick from.
I was actually going to send the person the entire graphic sheet that I am using in the game to know what I am looking for.
What I need is a robot sprite walking up, down, left, right and in idle mode. Then two types of walls, a box, and magnetic fields in four different direction, an animated teleporter, a death sprite and an exit door animated. That's it. The animated sprites only two frames.