Are there any natural herbs or remedies that can help with ADHD along with meds prescribed by the doctors?

No. There has been one study showing some help with use of an extract from a tree bark and one study showing some help with use of fish oil products, but these have been small studies. However, many parents do use melatonin to help children sleep who suffer from insomnia because of their adhd or the medications used to treat it.
Hmmm. Michael bloch, md, assistant professor at the yale child study center at yale university school of medicine commented on a review of over six hundred patients showing a minimal help in using omega-3 acids in adhd patients. He cautions however, that the effect is minimal, and does not supplant mainline treatment.August 16 in the journal of the academy of child and adolescent psychiatry.
Omega-3 plus meds. Omega-3 oils support the brain and nervous system. Omega-3 supplements have been used alone and in conjunction with traditional medications for treatment of ADHD.