Black and white contrast is attractive for newborns. (You can substitute red or dark blue for black.) Here are some crafts you can do by yourself or with older children that you can then show to your newborn.
I did this one with Natalie just before she turned two, but really a person of almost any age can have fun with this. I provided Natalie with black and white finger paint, black and white paper, and paint brushes. Any designs she made were high contrast. She made some swirls, globs, lines, and hand prints. You could also provide different utensils to make the designs, such as whisks, cookie cutters, or spatulas.
At the dollar store, I bought a few packages of foam sponges in different shapes (sea animals, basic shapes, and transportation). I then just stamped the sponges in black paint and then again on a white piece of paper. You could get more complex and alternate background and paint colors. I made a simple poster, but you could make a fold out that stands up for baby to look at during tummy time or a booklet.
I took two pieces of construction paper. One piece I cut into stripes about an inch wide. Then the other piece I made slats the whole length of the paper LEAVING ABOUT AN INCH BOARDER ON THE SIDE. I then weaved the strips in and out of the slats. To keep it from falling apart, I used Scotch tape on the edges.
Soft Needle Point Cube
I have the idea for this one, but haven't tried it yet. I plan to make a block using cloth needlepoint fabric. Each side will have a different patter, like bull's eye, stripes, zig zags, and checkers. Then I will sow the sides together and stuff the block. Might put a bell inside, too.