I've had great success with my George Bailey  themed gift from It's a Wonderful Life:

Basically, you find a lovely basket, fill it with decorative ‘grass’ and add a loaf of bread, a container of salt and a bottle of wine. You can print and frame this saying or have made a nice wooden sign made they can hang in their kitchen that says:

Bread! That this house may never know hunger

Salt! That life may always have flavour

Wine! That joy and prosperity may reign forever!

Cutting boards are a good choice. I give a lot of the glass cutting boards, some are very beautiful as well as useful.

I give a reusable shopping bag filled with the same theme as Susan's Basket, but the shopping bag is branded.

Evelyn Johnston This is a tuff one! During the time i  am shopping  with the buyers I am listening to them. Do they like golf, do they enjoy traveling, do they hate the exisitng mail box, etc. 

Once I have a good idea of their hobbies and activities they enjoy I can buy them something they value. If she loves baking the gift may be an amazing mixer!

My office does a really nice cutting board with the buyer's name and date of closing.  On the back side of the cutting board the office add their name.

Cutco the knife company had a display at our State Convention. They said their gifts never go away and get used over and over. It is agent branding.

I often gift key rings with a house and either their initials engraved on it or their closing date. I also like to do interesting return address labels (Colorful Images a great source). A door knocker with their name engraved on it is a good choice, too, as long as they aren't buying a home with a glass door.

I always give away a personalized cutting board.  If the price is big enough I also give away an engraved knife or pair of knives with my name and number engraved on them.

Good morning Evelyn. Many of my Realtor referral partners are giving Starbucks or Dunkin Donut gift cards, they always seem to be a hit.

I gave coffee cards like Starbuck. Make sure you validate there is money on the card.... My wife bought cards there and they did not validate .....Oops...

Target, Macy gift card etc...

I can make a few suggestions for those that don't listen to their agent and take their own steps!

I was going to say Cutco Knives too.  You can get them engraved with the family's name.

Gold Star cookies LOL

An original painting of them and their home by a famous Elkhart artist.

I'm not into gift giving, but some of the ideas I've heard that make sense are, Home Depot or Lowes $50- $100.00+ gift cards, Gift Certificate from local locksmith so owners can have all new door knobs and locks installed, Some type of art work ( or gift certificate etc fineartamerica, etc, Gift certicate for outdoor firepit from local landscaper, bird houses, new mailbox ( see houzz.com) .