Ive been to many bridal showers and weddings thats why I already gave out those things :)
My cousin had one and my aunt told my mother that a great idea would be cash for the gift. That let a bad taste in my mouth, especially because this couple were given the down payment for their house, etc.
I have given engagement gifts to people who were close to me as a keepsake of something I think they would cherish. Most recently when my best friends children were married, I gave them champagne glasses when they became engaged, so that they could use on their wedding day and in the future to commerate their marriage.
Nothing is necessary except death.