Pre-made Cream
My sister recommended Young Livings diaper rash cream to me and it has been amazing. There are no harsh chemicals, only natural products including; Mango butter, German Chamomile oil, and others. It has been the only pre-made product that I have tried that has worked for my girls.

Homemade Cream
If I am short on funds, which has happened often in the past, I end up making my own cream. I fill a 4 ounce mason jar with half Shea butter and half organic Coconut oil (you may use all shea or all coconut if you do not have the other). Then I mix in 1-2 drops of Lavendar essential oil, 1-2 drops of Gentle Baby essential oil, 1 drop Rose essential oil and 1-2 drops Purification essential oil. apply during diaper changes.
This is my favorite blend, but you can add or subtract oils depending on which benefits you would like. For example, I add the Rose oil because it is very good for the skin and has been used for thousands of years. It can also work as an anti-inflammatory and provide antioxidants for the skin. It is one of my favorite oils.
Regardless of which oil blends you use it is important to remember that Baby's skin is very sensitive so be sure to dilute any oils that you use for them to at least 50:50
*These statements have not been evaluated by the FDA