Red Dot Sight - I just took off the outer part of the default crosshair and painted it red. I also added some light shading around the edge to give it more of a "Laser-Pointer" feel.
FPS Crosshair - Based off the "Color-Blind" crosshair from Left4Dead. I just shortened the FPS Crosshair from the crosspick client mod and whitened the inside, then darkened the outside.