In a toy shop you can buy all kinds of infant toys, but most of the times common, hand-made toys, are what infants prefer.
In my opinion a nice hand-made toys is the infant’s bottle case: To build one on your own you need a bottle case (it’s best when you use a bottle case for 0.5 ml oder 0.75 ml bottles) and empty and cleaned bottles without labels. Ensure to remove all parts on the bottle case or the bottles (e.g. the plastic stripe on the bottle cap) that are sharp-edged. When you have done that, most of the work is already done. Now you can fill the bottles with different materials: water, coloured with food colouring, small bells, rice, dried raisins, dried peas, feathers or anything else that can be put into the bottles. Of course you can take different bottles with different design and form or you can paste them up.