I have a fairly basic (but IMO good) list of abs conditioning:
- pike-ups on the regular floor
- pike-ups with legs against a wall (feet up, only lifting chest)
- scissor pike-ups (one leg up at a time alternating and bringing chest up every time a leg comes up; this should be done quite fast)
- hollow hold
- rockers (on all four sides)
- front support hold on elbows (toes tucked under; this is a lot harder than it sounds)
Hope this helps.