This metal miniature is an Eldar Farseer from the Rogue Trader era of Warhammer 40K. It’s a 1990 Jes Goodwin sculpt as per the 1991 Blue catalogue.
It has “FARSEER” on the front and GW 1990 on the rear of the tab. It’s shown as part number 071604/3 in the 1991 catalogue.