There are deities with more than 2 legs.
Agni
The image of Agni in temples, represents him as an old man with red
body. He has two heads, a big belly and six eyes, seven arms in which
he holds objects like the spoon, ladle, fan etc., seven tongues, four
horns and three legs.
Hindu Gods and Goddesses, The Vedic Gods by Swami Harshananda
Yajna
Visnu has been identified with Yajna or sacrifice in early Vedic
literature. ................ His image has two heads, seven hands,
three legs and four horns.
Hindu Gods and Goddesses, The Trinity Vishnu by Swami Harshananda
Mahakali
.. Mahakali has ten faces and ten feet.
Hindu Gods and Goddesses, Sakti or the divine power as the Goddess Durga by Swami Harshananda