Uncooked beans (legumes) contain a toxin that is released when boiled. If you're thinking of making a "Chop" or "mash' recipe with seeds,beans,fruits, veggies, and pellets, always, always cook the beans,
Uncooked rice can expand in the bird's crop and be fatal.
An obvious one is electrical wires. My bird has chewed through one computer A/C adapter without my realizing. Now I'm very vigilant about where she is and what she's doing, even when she's playing solo.