There aren't really freebies. (nothing useful or cool anyways, more like samples you can't do anything with)
But- let them know to just register at every store they might buy ANYTHING from after the wedding!
Stores now send you coupons after your registry ends. Sometimes they will say it's 10% off anything left on the registry- but often you can buy anything in the store with it. Or they can just go in and register for random other stuff they will want to buy and then get the discount.
We did that at Target and (not sure if you still can, but) you could go in and add stuff to the registry after the wedding date. So I got our coupon in the mail and then added a bunch of stuff (clothes for my daughter, groceries, movies etc) and got the discount. They could even just open a registry that was all toiletries they normally would use and stack the registry coupon with regular coupons.
In the future, if it comes up, this works with baby registries too.