(I don’t have ADHD, but I have relatives who do, and I have been trying to educate myself by reading various books and online resources, and by lurking on the ADHD subreddit.)
Possibilities I have considered include:
- Alcohol — at least for social-lubricant purposes
- LSD or related chemicals — I’ve seen claims that low doses of LSD enhance creativity
- MDMA — makes people more talkative; “improved pattern recognition”, Wikipedia says
- antipsychotics — affect the dopamine-seratonin balance, a part of brain chemistry that is also implicated in ADHD; I don’t see much related to attention in the description of antipsychotic drugs’ effects, but one side effect that caught my eye was “akathisia”, the inability to sit still