Straight legged sit ups
Hanging Leg Raises
Leg Lifts
Crunches
Standing Abs
Spread Eagle sit ups
Bicycle Kicks
Since I have been using weight as resistance I have found my abdominal region to be considerably stronger. It makes sense to me to use weight and build that muscle. I never said it was big lol but it is strong.
I like incline sit ups with bands...full ROM like B fold said.I also like flat sit ups with a plate behind my head,or a band,and hanging leg raises with no weight.That and training without a belt has seemed to help me alot