The plank is accepted as a basic exercise for building core strength. There are many possible variations of a plank. Not surprisingly, there are TRX plank variations as well. The seventh variation on the following webpage is not one I'll ever try. It's a handstand with one foot in the TRX!
7 TRX Plank Variations
TRX rotational ward
TRX plank
TRX side plank
TRX 1-arm plank
TRX forearm plank
TRX single leg plank
http://www.acefitness.org/blog/5693/7-trx-plank-variations-for-a-stronger-core
For those familiar with TRX exercises, this webpage is a nice summary of core exercises. If you don't know an exercise, finding a video on YouTube is fairly easy when you know the name.
20 TRX Core Exercises
Overhead back extension
Hip drop
Torso rotation
Kneeling roll-out
Kneeling oblique roll-out
Standing roll-out
Overhead squat
Assisted sit-up
Resisted single-leg raise
V-Up - heels in cradles
Suspended plank (elbows or hands)
Crunch (elbows or hands)
Oblique crunch
Mountain climbers
Pike
Pendulum
Body saw (elbows or hands)
Side plank (on elbow, with or without arm assist)
Side plank with hip drops
Side plank with reach-through
http://www.cyberpt.com/documents/CORE%20EXERCISES.pdf