These paintings of Tara surrounded by an additional twenty-one forms are conditionally designated as describing the Sadhana-sammucchaya Tradition. The only reason for this designation is because they do not fit into the Suryagupta system where each form of Tara has a different appearance, colour, numbers of heads, arms, attributes, etc. They also do not fit into the Atisha system where each Tara holds a vase in the extended right hand. They again do not fit into either of the two Nyingma systems where the principal symbolic attribute of the deity is depicted above the flower blossom on the left hand side.
It is very possible that other traditions and systems for describing the Twenty-one Taras will be found or discovered in rare religious texts.