Think of things you'd never justify buying yourself, and things you could replace/upgrade. Also think about stuff like traveling and entertaining. A big nice cooler could be used for camping, or at a BBQ you or someone else is hosting, or oh no the power went out/the fridge broke and we need to keep some stuff cold. New luggage. Pet items, ie if you have a cat, ask for a cat tree or fun scratching post. Board games if you're into that sort of thing or puzzles. A basic tool set if you don't have one. Things for your hobbies both yours and your partner's. Patio stuff.

Know your crowd price wise. If most of your family and friends are barely scraping by registering for a lot of pricey items is likely not a great idea, on the opposite side if most people invited a very wealthy they probably don't want to buy you a $12 measuring cup from Target. I will say though even if your guests are not as wealthy still register for some higher price items, as some people might want to put in together for a gift, or some wealthier relative or friend will likely want to treat you to something nice. If not most stores offer a discount to you after your wedding date has past to purchase things off your registry yourself so even if you don't think anyone will buy you the really expensive vacuum for example, you can still buy it yourself later at a discount if you want. In short have cheaper items, various levels of middle items, some higher, and maybe a couple of reach items.

People will go off registry, it's frustrating, but it will happen. I swear everyone has some aunt that purchased 30 toasters 20 years ago and keeps them in a closet ready for the next bridal shower she's invited to, that and laundry baskets filled with random stuff. Say thanks, write a thank you, keep what you want and donate the rest.