The Gloom: Unhappy Homes expansion adds one player and 55 cards to the game. Here is a description of the expansion from the publisher:
In the Gloom card game; you make your eccentric family of misfits suffer the greatest tragedies possible before helping them pass on to the well-deserved respite of death. Just mix the 55 transparent cards included in this set together with your copy of Gloom to add morbid new Modifiers; Events; and Untimely Deaths; and a new family -- the artistes of Le Canard Noir; whose creative endeavors always end in disaster.
When art lets you down; the Black Duck is there for you. This dingy cafe is home to a motley assortment of washed-up bohemians. Here the tormented painter Rosseau buys drinks for neurotic models and destitute poets; while a troubled actress and sickly courtesan compare notes across the way.
Also included are five Residences with a light blue background behind their central illustration. These are each placed next to their related family at the start of the game. New cards called Mysteries; which have a dark blue effects bar at the bottom; are also shuffled into the deck before play. A Mystery is the only card that can be placed on a Residence (and only a Residence); and can be placed on any Residence as either of your two plays. It gives that Residence's player a special effect and Pathos points that count toward his final Family Value. A Mystery remains even if the requirements for playing it are lost. You may discard a Mystery from your hand as a free play.