The line between medicine and drug is largely arbitrary.

Start with the basics of diet, exercise, water, sleep, social interaction. They're consistent and have very low harm potential. It's also shocking how much each of them contributed to a sense of well being, or how much a lack of any one of them can cause a downward spiral.

Supplements and vitamins also aren't super risky, although they aren't well regulated and many do nothing in their pill form. One or some of the vitamin Bs seem important for me personally, although I'm not 100% certain and I don't know which one(s) and to what degree. But I'll drink a monster energy regularly because they have 200-400% dv. Omegas from fish oils may also be good. L-tyrosine and things like it are commonly discussed in nootropics boards, I can't vouch for them personally.

As far as medications, it's unlikely you'll find an easy and risk-free solution, unfortunately. Even well-studied prescription medications aren't guaranteed to work for your specific needs and have potential to make things worse, which is why in an ideal world everyone would have access to a medical professional that can oversee their use. And often the ones that work aren't immediately obvious, but demonstrate marginal improvement over the longer term. In fact euphoria and hypomania (which in the moment feel like "oh my god this drug is working") may be signs the drug isn't a good fit. Very difficult to gauge on your own.

Online prescription mills are fairly painless if you have a good idea that a specific medication might work for you. I used them to get on a specific antidepressant after doing my own research.

Kanna and St John's wort both have SSRI compounds I believe. Be careful, just because something's a legal plant doesn't mean it can't interact negatively or have harmful effects. But these are probably the closest to what you're asking.

Kratom is legal and can boost mood but has high addictive potential. In my experience not worth it except to get off more addictive substances.

Dex/dxm/dextromethorphan is an active ingredient in some cough suppressants that has antidepressive potential. Can be purchased with no additives at some pharmacies and online. Tripping on this isn't fun at all in my opinion, I'd rather do salvia, but small doses seem to have some mood improving effects that last a few days

Stay away from diphenhydramine (I mention it because it's often spoken of in the same context as Dex). Its use has been linked to dementia.

Psychedelics can help deconstruct old assumptions and mental structures that may be contributing to your depression. I'd describe the experience as rediscovering the magic of existence. Many of them also have antidepressant qualities-- a sort of afterglow that may last a week or a month. Microdosing is said to tap into the afterglow without tripping. LSD and shrooms are fairly well-studied. Mescaline acts similarly and may be easier to find. Morning glory seeds are legal and contain LSA which is similar to LSD. Salvia acts differently than any of these, often leading to bad trips, but is generally legal. None of these are addictive, but may be risky for people with certain mental illnesses.

There are a variety of legal and grey market stims that can improve mood, but they may have harmful effects and addictive potential. You'll find a bunch of them if you browse nootropics boards, but keep in mind anonymous comments are not scientific and may undersell risk and negative effects. Nootropics boards will also discuss other supposedly cognitive enhancing substances. Lions mane is a common one. Some are natural supplements or things your body already produces (though this doesn't guarantee they're safe or pure). Many are addictive, many are probably snake oil. Search a drug/supplement on pubmed before trying it.

Adjacent to nootropics and more dangerous is research chemicals. Half of them are attempts to make "legal" but identical/similar analogues to illegal drugs. Some are novel. Almost none of them have been studied and purity is never guaranteed. I Honestly don't recommend unless you're at a point where it doesn't matter. At one point for me it was "find a happy chemical or commit suicide" and I think that's the only level this kind of experimentation is truly justified. But well-studied psychedelics are preferable.