There are unlimited ways to make variations of frittatas. Use leftover cooked vegetables and proteins in frittatas. Try different kinds of cheeses. Make mini versions to put in your lunch by cooking the fritattas in muffin tins. These freeze really well for breakfast on the run.
Instead of cooking in a frying pan, allow cooked vegetables to cool. Then mix in to the egg mixture, and pour into greased muffin tins. Bake mini frittata for ~20 minutes at 400 degrees.