-It is most prominent Yantras of deities (these are usually forms of the Great Mother or the Mahavidyas - 'Sources of supreme knowledge').
Example: Shree Yantra, Lakshmi Yantra, Kali Yantra, Durga Yantra etc.
-Used to harness the energies of the nine major planets.
Example: Yantra for Sun, Moon, Mars, Mercury, Jupiter, Venus, Saturn, Rahu, Ketu.
-Used for the ground plans of temples.
-Mathematical Yantras are based on a particular sequence.