In an earlier post, I mentioned the developmental capabilities of infants vision
"It is believed that infants leave the womb with many of their senses not fully developed. For example, the colours infants can see best at birth are black and white. Infants vision is also not developed enough to see most things clearly unless they are about 8 to 12 inches away from their eyes".
Masha'Allaah, Smart Ark.com has some very cute black and white flashcards for baby that you can download for free.
These would be nice to laminate and during babies quiet focus time, present them to baby one at a time allowing him/her to focus on them for as long as they show interest. For infants who are able to grasp objects, if the cards are laminated, and the corners are rounded, you can place the card in the infants hand and allow him/her to look at the card as long as he/she wishes. For babies who are not yet mobile and cannot grasp objects, you can prop the card up on an object that is directly in front of baby and allow him/her to focus on it insha'Allaah. In all case, parental supervision is advised.
You can download the cards here insha'Allaah.