Pilates would be a good choice, and some yoga or tai chi. Low weight, high rep strength training on the upper body would burn some calories. Or the treadmill or elliptical, start slow and stop when the ankle starts to hurt. A stationary bike might be OK but I'm not sure if the pedaling would flex the ankle too much. Maybe a rowing machine? I'd avoid high impact stuff, jumping, running, aerobics etc. Listen to your body and if it hurts, don't do it
I walk a fine line between working out and hurting myself all the time, it's better to move but you might have to take it slower than you'd like.