Here Vishnu is holding Gada, Chakra, Shankha and Padma (Mace, Discuss, Conch shell and Lotus) in his hands, clockwise starting from his lower right hand.
Kneelength Vanamala, his standing on a tortoise and the presence of Garuda, his vahana, by his side are the notable features of this Vigraha. It is unusual to see Vishnu standing on Kurma (Tortoise), given Kurma is one of his Avatars.
Stylistically this is a mix. But it is most likely it is from North Karnataka/Southern Maharashtra region.
The book The Singer’s son (Ganaryache Por) by Raghavendra Joshi, Dr Bhimsen Joshi’s son, has a photo of their family altar. See below and in the photo, the Vigraha on our left bottom is remarkably similar to the subject of this blog. The significant difference is the Garuda facing Vishnu. Thanks to Swanand for the information and the photo.
This Vigraha is about 8 cm in height and may be dated to the 18th century.