I make a big batch of a base which includes mostly grains including quinoa, oat groats, red wheat, amaranth, and whatever else I have around. I add dry rolled oats when it's done so I can absorb as much water as possible. The dryer your mix the better it will be when frozen.
Every other day I'll pull out a baggie and put it in the fridge to start to thaw, rough cut whatever veggies I have that day, to fit in my food processor, buzz it a few times, heat up the base in the microwave, mix it all up, sometimes add hot pepper flakes, cinnamon or peanut butter powder (not PB2, which has added salt and sugar) depending on what else I added, mix it all up and serve. I'll usually do things like fruits with cinnamon, or veggies with hot pepper flakes, banana and powdered peanut butter, etc.
I have a big variety of packaged frozen vegetables, mixed, peppers, zucchini, carrots, as well as a few different kinds of frozen fruit. I grab whatever's on sale, and since my mom's currently staying with me, she asks "Which is for us and which is for the birds?"
My mix ends up being a decent variety, and you don't need to spend too much time on it. It's fine to mix some canned or frozen with fresh, and since my birds are usually getting things I'm eating, I'm not worried about variety. If I'm making pancakes, you know my fids will be getting a few little pancakes stuffed with fruit or veggies. If I'm cutting an apple for myself, they'll be getting half. I don't think I can even eat my cereal without them getting some!