The Side Plank trains your lateral core to resist lateral flexion (or side-bending) and rotation. It can be performed on the forearms or hands. The forearm variation is more of a strength challenge where the longer-lever hands variation is more of a stability challenge. Train both positions for best results. You can either stack the feet (harder) or stagger them (easier). Make it easier by elevating the hands. Make it harder by elevating the feet.
The exercise can be further regressed by bending the knees at 90-degrees. This is called a short-lever side plank. The top 2 progressions involve elevating a leg. Elevate the top leg (abduction) to work your lateral glutes more. Elevate the bottom leg (adduction) to work the groin more.
The rolling plank is an excellent option because you’re flowing between 3 main plank positions: left side, front & right side. My favorite variation is the side plank to pushup transfer because you change levels and move in all 3 planes of motion.