Gold jewelry, but that is usually given by the bride’s parents. Some people give really nice sarees to the bride. Pretty much anything you would give to an American couple is good to give to an Indian couple; just make sure the voltage is compatible if you are giving an appliance.
buy them something they need for their house.. like wine glasses, or a pretty vase or picture frame.
“jcullum” has given the best answer. Usually you give money to the couple at their wedding but you have said that you wish to give something else. Therefore, jewellery.