Does anyone know whose seal this is?

Kuang 'an is the word or name of many famous people in ancient times. However, the "Kuan 'an" seal that people see in paintings and calligraphy works is mostly a person named Gao Dai.

Gao Shiqi, a famous scholar and collector in Qing Dynasty, collected countless paintings and calligraphy works all his life, most of which were handed down to later generations.

Kuan 'an is Sun's seal.