Some producers include roasted peanut during chocolate production so peanut butter may be a viable alternative but issues such as allergies should also be considered. In addition, peanuts are among the crops that are most susceptible to mycotoxin contamination, especially when not stored rightly, so you should also look out for this if you are thinking of large scale productions.
Peanuts, but depends with availability in your locality, some hydrocolloids also act as fat replacers depends on where you are and what you can find easily