Wooden Blocks
Wooden blocks are a classic baby toy, and for good reason: babies love to stack them, beginning at about this age. Ten-month-old babies are able to better manipulate objects than before, but their hand control isn't yet perfect. After stacking four or five blocks, they may inadvertently knock them all down---to their surprise and delight---making it a game of stacking and crashing.
Balls
A bouncy ball that's small enough for a 10-month-old baby's hands, but not small enough to fit into his mouth, can provide interactive fun as well as a lesson in physics. Sit on the floor with your baby and roll the ball back and forth, or hand it to him while he's standing and watch him drop it. Balls are unpredictable for babies, and give them different outcomes when they throw it, drop it or roll it.
Toy Telephones
Realistic-looking toy telephones---especially toy cellular phones---offer 10-month-old babies a way to imitate their parents and interact with them. Babies at this age babble into the phone, holding a one-sided conversation with pauses and tonal changes, just like their parents.
Containers
Moving objects and filling and emptying containers are two fascinating processes for 10-month-olds. Use two small laundry baskets or two clear plastic containers to transfer objects, such as stuffed animals, from one to the other---demonstrating the difference between empty and full. A bucket and shovel work in much the same way outside in the yard or at the beach, as babies fill their buckets with dirt or sand and then dump them back out.
Push Toys
Push toys are ideal for babies who are learning how to walk. If they're weighted, they offer some support for standing babies to push into while taking those first steps. Wagons and little cars are more heavily weighted than little wooden push toys with stick handles, such as a dog on wheels. Pull toys are reserved for walkers who can look behind them while walking forward.
Noisemakers
Babies at this age have longer attention spans and are fascinated by sounds. Any noise-making toys that are safe for them to play with offer an opportunity to learn. Pots and pans and wooden spoons are tried and true makeshift noise toys. An unopened box of rice makes a different noise, as does a handful of popcorn kernels in a tightly lidded plastic bottle.
Sorting Toys
Problem-solving skills are more developed---and continue to develop rapidly---in 10-month-old babies. Shape-sorting toys offer a challenge to this developing skill. Babies learn quickly that a square block won't fit through a round hole, and may experience a little frustration and intense concentration as they go through this trial and error.