Welcome to TBN. What is your fuel usage per hour? What do you primarily use the tractor for? It's hard to recommend a tractor that will use less fuel if we don't know what you're doing with it.
Cat D3, Deere 110 TLB, Kubota BX23 and L3800 and RTV900 with restored 1948 Deere M, 1949 Farmall Cub, 1953 Ford Jubliee and 1957 Ford 740 Row Crop, Craftsman Mower, Deere 350C Dozer 50 assorted vehicles from 1905 to 2006
Since day 1 I've been amazed at how little fuel my BX23 TLB uses... I can often go a month on on a few gallons...