Supplements: magnesium, B vitamins. Vitamin D (from sunlight)
The right dose of phenylpiracetam, caffeine, and Huperzine can be just as effective as low dose adderall in my experience. Although the side effect profile is completely different: less hyperfocus, little impact on appetite, much more irritability.
However I have to say that lifestyle is BY FAR the most effective treatment (even more than adderall, especially long term) and it always bothers me when people ask for advice for supplements and drugs only.
Sleep 8-10 hours per night, eat a good breakfast, don’t use nicotine, exercise every day or almost every day, get some sun. Not only do these help by themselves but they also make medication like phenylpiracetam and adderall (adderall in particular needs a lot of protein to work best) more effective as well.
Also I highly recommend taking a >1mo total break from cannabis if you are a frequent user. I find that as my usage gradually increases so do my ADHD symptoms, until I quit and suddenly have much more energy and motivation in the next few weeks as my body flushes it all out.