I represented the buyer in a transaction where the MLS indicated that the washer and dryer were included, but after closing we realized the sellers had taken those appliances. Do we have any recourse?

The closing is based upon the items outlined in the purchase agreement, and the purchase agreement supersedes the listing information. Even if a non-affixed item is referenced on the MLS as being included in the sale, you will always want to reiterate that information in the purchase agreement. Also, to avoid newer appliances being replaced before closing with older models, you might even be specific in the purchase agreement as to the make/model of the appliances or perhaps indicate that the transaction will include the appliances that were in the home on the date of the showing. There have been many agents over the years who have neglected to do this and then found themselves chipping in toward the cost of appliances in order to maintain a positive client relationship.