Try asparagus it will pay for it'self. Try flowers, I have found many things grow better with flood and drain. Tomatoes are doing ok in the Matt system with contineous flow. I can only eat so much lettuce so have started Bok Choi, spinach. I have found celery hearts will root and continue to produce, so will horseradish, onions, garlic, any number of veggie leftovers will come back and produce. Cuttings root easily with the bell siphon etc.
Add a bucket worm bed to your system your plants will start smiling. And that is free! Go green!