Tropical plants, ferns, palms, and orchids like it steamy and should steer clear of heating contraptions that will dry them out. These plants will love hanging out in more humid rooms such as the kitchen or bathroom.
You can add pebbles and a little water to their saucer to boost humidity. Replace the water with a fresh batch from time to time and don't let pots sit in the water... prop them up so that they are above the water level. Group plants together to create a more humid microclimate as they release moisture through transpiration. They will also appreciate being misted every few days in addition to their normal watering to imitate a humid environment. You could also invest in a humidifier. They come with the added bonus of improving your own health, skin and sleep quality. There is no need to mist cacti and succulents in-between waterings… nothing will make them more homesick for the desert. Like all plants in your home, consider where they come from and aim to emulate their natural habitat.