Do you have access to a gym? The rowing machine would work the back (mostly other muscles but it helps with the back too).
These work multiple parts of the body but the back (either the whole back or the upper or lower) is apart of the exercises below.
Dumbbell shrugs, one arm dumbbell row, seated dumbbell row, airplane pose, t stand, reverse plank, bridge-ups, single leg bridge-ups, bridges
| Pounds lost: 24.3