This is a hard one. I went to the health food store today and read shampoo bottles for about an hour. This was bad because I had my two-year old with me. Unfortunately, I was disappointed and found NONE. All the shampoos use some kind of coconut product. So, online I found some:
Natural Shampoos, have small samples available. Not a traditional lathering shampoo, but gets the job done well. Be careful which one you choose, some have changed their formulas recently.
Clean Kids Naturally - it's a baby shampoo that smells like orange. VERY gentle, Love it. We have used it on ourselves and our babies for a year or more now.
Go shampoo and conditioner free! This blogger tells how to use baking soda and apple cider vinegar.
Let me know if you've tried any of these or any others!