what drugs, and or supplements help the most to regrow
A few names, but not of proven benefit.
I read your question carefully and I understand your concern, I see that you must have done some researching yourself and are aware of the scarcity of alternatives for nerve regeneration.
If you mean drugs which have been proven beneficial for that purpose I am afraid you will be disappointed as there isn't a list of such drugs. Lithium and SSRI antidepressants like fluoxetine (Prozac) and sertraline are thought to provide some benefit but it is a question of small scale studies mainly in animals. There haven't been any large clinical trials in humans, not approved in any dosage for that purpose. Other alternatives under study include baclofen, valproic acid, pregabaline, gabapentine. There may be other, but however it is a modest benefit not proven by large scale human studies, not approved and prescribed for that indication in everyday practice.
As for supplements vitamin B12, B1 and B6 supplements, alpha-lipoic acid, L-carnitine, fish oil and curcumine are the most used ones. As for medications the lack of studies proving benefit applies to supplements as well I am afraid.