There are different groupings of the Eight Great Adepts that have been depicted in art over the past 1000 years. The earliest representations of eight siddha figures are found on sculptural Lotus Mandalas of India and Nepal. The Sakya and Kagyu traditions placed identifiable mahasiddhas in painted mandalas with each associated with a particular direction. Dolpopa Sherab Gyaltsen wrote a famous praise to the Eight Siddhas based on a vision. Numerous other teachers through the centuries wrote about the Eight Siddhas or composed their own favourite eight Indian mahasiddhas.
Situ Panchen Chokyi Jungne in the 18th century designed his own compositions illustrating his selection of the eight siddhas based on various earlier Karma Kagyu systems. These compositions were copied again and again leaving a wealth of examples in museum and private collections worldwide. See the Eight Siddhas as minor figures in early artworks: Eight Siddhas (misc.)
*Lawapa does not appear to be included in any of the early systems of the Eight Siddhas. In the 18th century, Situ Panchen Chokyi Jungne, the founder of Palpung monastery, substituted for his own purposes, the mahasiddha Lawapa and removed Luipa from the set. The Palpung painted representations of the Eight Siddhas are very well known and many copies were made in various compositional sets.
Jeff Watt [updated 5-2018, 4-2019, 11-2021]
(The images below are only a selection of examples from the links above).