Some sites that provide a wide range of holiday e-cards, such as Care2, 123Greetings and Got Free Cards, also offer Diwali e-cards, some of which are animated. Other sources include Hindu promotional sites such as Diwali Habba.
Diwali is the Hindu festival of lights that is usually celebrated around November. The date changes each year because it is based on the lunar calendar. Cards for Diwali greetings popularly feature sparkling lights, flames and fireworks, all of which work well as animated designs. Cute representations of Ganesha, the elephant-headed god of wisdom, are also popular. Hinduism.about.com provides more information about the festival and offers more animated e-cards.