Here are some names to start things off:
Could you tell us a little more about what you're looking for in terms of style? For instance, what are the names of your three older children? What names are you currently considering for baby #4? This sort of info will help us make even better suggestions.
One thing I would suggest at this point is to avoid names that end with C or K (like Patrick, or Isaac) because that C/K sound will blend with the C of Clayton. (It would also be wise to avoid names that could blend with your surname in the same way.)