You can sprout almost any kind of seeds that have not been treated with a sprout inhibiter.
I buy wheat berries, whole oats, and other seed from the co-op or directly from the feed mill in 50lb bags. I have sprouted scratch but the seeds in it don't all sprout at the same time and some don't sprout at all.
If you don't have many birds and you just want to sprout for treats, you can buy lentils, blackeyed peas, whole barley or other grains/beans from your local grocery store. There are lots of good articles here on BYC that will instruct you how.
Good luck!