There are a large number of ways to perform these movements.  You can use low weight lots of repetitions, high weight with low repetitions, super set, or perform circuit type training.   Not only can you adjust the style of training but you can adjust the type of tools used to complete the exercise.  Tools include Dumbbells, cables, bands, body weight or machines.

There are so many ways to train – I use bodybuilding.com Exercise Guides and Workout Database, magazines and YouTube to help me design my workout routines depending on my goals.  Right now I am trying to build muscle but in a few months I will adjust my training and lean down while retaining as much muscle.  Remember to switch things up every 6 to 8 weeks.  Keep your body guessing by adjusting your style of training to fit your goals.

If you are not sure what some of the following exercises are, copy and paste the name into the Exercise Guide on bodybuilding.com to find pictures or descriptions.

ABS

Russian Twist
Decline Russian Twist
Med Ball Rotations
Hanging Leg Raises
Decline Leg Raises
Decline Situps
Swiss Ball Situps
Standing Rotations using Cable and Swiss Ball
Med Ball Woodchops
Sprinter Situps
Swiss Ball Knee-ins
Swiss Ball Roll-outs
Wheel Roll Outs
V-ups
Crunches off Edge of Bench
Rope Pulldown Crunches
Weighted Situps
Crunches Roman Chair Situps
Grappler Twists
Plank
Side Plank
Med Ball Slams
Straight Arm Cable Twists
Windmills