I think my favourite move is the Spiral Armbar. It’s a specific submission where you can use your hips and your body for leverage against the person's arm. That increases your likelihood of finishing the submission.
“Since my first class, I have lost 60 lbs, had a total body transformation, gained an incredible amount of confidence, and found a new family with my Champions Creed Staff and Members! The best thing I ever did was walking into my first class.” -Angela White