Here is a great workout with just using variations of PLANKS. The way I have it setup is the exercises before the first REST interval are the Beginners level. Once you have mastered these to the sets (or even longer time or reps) then move to the exercises in between REST. This is the Intermediate level planks. Once these have been mastered, then move to the final exercises after the 2nd REST to be in the Advance level. You can always intermingle all the exercises for a great challenge.

Full Plank 3 sets x 1 min Rest 90 sec between sets
Elbow Plank 3 sets x 1 min Rest 90 sec between sets
Plank To Push Up 3 sets x 10 rep Rest 90 sec between sets
Side Full Plank 3 sets x 1 min Rest 90 sec between sets
Plank Hip Twist 3 sets x 10 rep Rest 90 sec between sets
Alternating Single Leg Plank 3 sets x 10 rep Rest 90 sec between sets
Alternating Elbow Plank 3 sets x 10 rep Rest 90 sec between sets
Alter Elbow Single Leg Plank 3 sets x 10 rep Rest 90 sec between sets
REST
Suspension Full Plank From Hand 3 sets x 10 Rest 90 sec between sets
Stability Ball Full Plank 3 sets x 1 min Rest 90 sec between sets
BOSU Dome Down Full Plank 3 sets x 1 min Rest 90 sec between sets
Suspension Side Full Plank 3 sets x 10 rep Rest 90 sec between sets
REST
Star Side Full Plank 3 sets x 10 rep Rest 90 sec between sets
Spiderman Plank 3 sets x 10 rep Rest 90 sec between sets
Stability Ball Elbow Side Plank 3 sets x 1min Rest 90 sec between sets
Battle Rope Slams Full Plank 3 sets x 10 rep Rest 90 sec between sets

Full Plank
1) When performing this exercise, you’ll want to maintain an active core which means glutes and abdom holding neutral spine.
2) Place your hands directly below your shoulders and maintain throughout.
3) Lie face down on a mat with your legs straight, feet together, hands on the floor.
4) Raise your body up into the top of a push-up position, on your hand and toes. Keep your back flat by drawing in your abdominals, and squeezing your glutes. Hold this neutral spine position actively.
Elbow Plank
1.Lie face down on a mat with elbows resting on the floor next to your chest, palms facing forward or in a fist position, feet together.
2.Push your body off the floor in a pushup position with your body resting on elbows or hands.
3.Contract the abs and keep the body in a straight line from head to toes. Hold for 30-60 seconds, then lower body returning to starting position.
4.Repeat.
Plank To Push Up
1.Lie face down on a mat with your legs straight and arms tucked in by your sides with elbows bent.
2.Raise your body up into the top of a push up position, resting on your hand and toes and hold briefly. Keep your back flat and head looking down at the floor.
3.Return to starting position.
4.Repeat required reps.
Side Full Plank
1.Lie down on your side. Stack your feet one on top of the other.
2.Prop yourself up arm straight, raising your hips and resting on your elbows.
3.Hold based on recommended time.
Plank Hip Twist
1) For this exercise, keep your abdominals active and glutes on.
2) Start getting into a plank position. Elbows beneath your shoulders and a nice straight line throughout your body.
3) Slowly twist, dropping your hip from side to side.
4) The goal is to twist your body as much as you can to get a full rotation.
Alternating Single Leg Plank
1.Support your body off the floor, resting on your toes and forearms.
2.Raise one leg straight up off the floor, keeping your body in a straight line and your back neutral/flat.
3.Lower back your leg to the floor returning to starting position.
4.Raise the opposite leg. Alternate sides with each rep.
Alternating Elbow Plank
1.Support your body off the floor, resting on your toes and elbows.
2.Raise one arm and the opposite leg straight up about 18 inches off the floor.
3.Hold briefly, then lower your leg and arm back to the floor returning to starting position.
4.Repeat with the other arm and opposite leg. Alternate sides with each rep.
Alternating Elbow Single Leg Plank
1.Raise your body off the floor on your elbows, resting on your toes.
2.Raise one leg straight up off the floor, keeping your body in a straight line and your back neutral/flat.
3.Hold briefly, then lower back your leg to the floor returning to starting position.
4.Raise the opposite leg. Alternate sides with each rep.
Suspension Full Plank From Hand
1.When performing this exercise, keep your arms extended as well as maintain a shorter distance between bottom of your ribs and top of your hips.
2.With your feet suspended on the straps, get into a plank position by balancing your weight on your hands, arms and elbows straight.
3.Keeping your body straight, lift your hips off the floor.
Stability Ball Full Plank
(1) Place your hands equal distance apart on the stability ball. Extend your arms until they are straight, and center the stability ball underneath you with your bodyweight equally distributed between both hands.
(2) Engage your abdominals and glutes. Slowly extend your legs out behind you one at a time. Move your body to make a straight line along your shoulders, neutral spine, hips, knees, and feet. Ensure your shoulders are directly above your hands.
(3) Hold for the prescribed duration of time, or until your form is lost (ie: not maintaining active abdominals, or not able to balance anymore).
BOSU Dome Down Full Plank
1) When performing this exercise, you’ll want to ensure your hands are placed equal distance away from one another.
2) You’ll also want to keep your abdominals engaged and glutes on to maintain neutral spine throughout
3) Raise your body to make a straight line along your shoulders, neutral spine, hips, knees, and feet. Ensure your shoulders are directly above your hands.
4) Hold for the prescribed duration of time, or until your form is lost
Suspension Side Full Plank
1.When performing this exercise, ensure your abdominals are engaged and your glutes are on to maintain a straight line to the side of your body.
2.To help balance through the upper limb, set your shoulder blade in a strong position.
3.With your feet suspended on the straps, get into a side plank position by balancing your weight on one arm.
4.Keeping your body straight, arms and elbows straight, lift your hips off the floor.

5. When you’re done this side, repeat on the other.