My late 2013 27” Quad Core i5 iMac with the GTX 775M. I got it for $50 at the thrift store. Magic Mouse 2 was included. Got it running Big Sur :) : r/macsetups
Apple iMac A1419, Intel Core i5-4th Generation CPU, 8GB RAM, 1TB HDD, NVIDIA GEFORCE GTX 775M Graphics, 27 inch Display