23. There are over 200 different varieties of philodendron plants that come in different sizes, colors, and leaf shapes. The Heartleaf or Sweetheart Philodendron has dark green, shiny, heart-shaped leaves and looks great as a table or hanging plant. Heartleaf Philodendrons are some of the most popular indoor plants we use in homes and offices because they thrive on neglect and are almost impossible to kill. Another great plus, philodendron plants remove air-born toxins such as formaldehyde from the air.