It can be difficult getting a gift for a one year old boy. Ask the parents about the boy's level of development so you get an item that is appropriate for him. Some boys walk and talk by this age, and your gift can encourage the boy to be mobile if he isn't already.
Get a large item if you want to splurge. Parents who have a large backyard might appreciate an outdoor play set with a swing and a slide. The one year old might be too young to play independently on the play set but he should grow into it by the end of the year. Or purchase a jogging stroller so the boy can enjoy the great outdoors with his mom. One year old boys typically outgrow their infant car seats so you could purchase the next size car seat in a boyish or neutral colour.
Boys typically need plenty of clothes because they are growing and get dirty. Purchase some practical clothes that can withstand a lot of use, such as soft stretch trousers and cotton T-shirts. A couple pairs of tennis shoes are useful at this age because the boy should begin to walk independently if he isn't already. Or go to a boutique to get a couple of nice outfits for the boy to wear to church and on holidays.
One year old boys typically enjoy toys that make noise and move. A push toy is beneficial for helping the boy learn to walk independently. Purchase a push toy that comes in the shape of a green dinosaur or a red car. Some push toys sing and talk, which can be very entertaining for a one year old. Or get some plastic animal bath toys so the boy can begin to have fun during bath time.
Purchase books to help the one year old boy develop linguistic skills. One year olds might tear thin pages so get books made from thick cardboard or cloth. Books with texture and bright colour can catch the attention of the boy. Some good books for one year olds include the Dr. Seuss series and "The Little Engine That Could." Even though the boy might not read yet he can flip the pages and look at the images.