Mudras are hand movements that are shown as a symbolic or ritual gesture or pose. Mudras are normally shown through hands, but some of the intricate gestrures use all parts of the body There are about 500 different meanings for their mudras. "The hundreds of mudras of Hindu and other related Asian dances are described in technical manuals, but, in practice, performers usually limit their gestures or “phrases” (sequences of mudras) to those familiar and meaningful to their audiences. The selection may differ from region to region"(https://www.britannica.com/topic/mudra). If you are just looking at Bharatanatyam there are only 55 mudras, and out of those 55 mudras there are 32 of them that are done on only one hand. A fun fact: During dance performances the dancers will wear alta on their finger tips, and on their palms. Alta is a bright red dye or liquid color, that is used so that the audience will be able to see the hand gestures more easily.
A few examples of mudras:
This mudra is called Pataka, and it means flag
This mudra is called Tripataka, and it means 3 parts of a flag
This is the third mudra and it is called ardhapataka, and it means half flag