A great way to quickly grow your collection with an ever-changing assortment of Peperomias and Pipers.  These relatives of Black Pepper have colorful, uniquely patterned foliage and endless variability, making for fantastic houseplants.  As a bonus, they're easy to care for, surviving with a minimal amount of fuss in bright, indirect light (though many will do fine with even dim light) and occasional watering when the soil begins to dry.