our neighbours have newly shifted in and invited us for a housewarming party. we don't know them at all. what are some good gifting ideas?

I think it will make sense to give something that is not too personal, since they are not really your friends yet, and also something that they can use. maybe you could try giving them one of those handicraft plant containers, that can be placed outside the door. these can be used dry as well as with water, and they can also use it as a decorative piece for their new home.