I like cable crunches for a start. I also use the power tower and do hanging leg lifts and knee ups. With the knee ups I'll add in a twist in order to target the obliques.
Even at my heaviest weights with a higher BF I can still see my abs.
As I drop BF they just become more defined.
You can see that at my lowest BF they are really pronounced.
Maybe what you think is 10% BF is a little bit off! How are you making the determination? I realize that not everyone is going to spend money on a bodpod test. I use a 7 point caliper test, Military tape test and a smart scale. If they are all in agreement then I figure i am with in +/- 2% of my determination.
Firstly, I complete my full workout, and after that, I give my proper time to cardio and abs training. Personally, I do crunches, planks, climbers, and cardio as well. But most important for abs is your diet so that you get a lean body or less fat.