For OTC drugs theres St Johns Wort.
I tried that first and had mixed results. The first brand I bought felt even more effective than SSRIs, but also had much stronger initial insomnia (SSRIs cause that very commonly and I had to also take hypnotics for 4 months too until it stopped), but then a higher dose brand I bought did absolutely nothing.
The main problem with St johns wort is that you cannot tell how effective each brand, and even each batch of the same brand will be as the active compounds are hard to standardise. The main compound that is standardised is Hypericin which is standardised to 0.3%.
The second active compound is Hyperforin, and this is apparantly very difficult to extract from the plant and standardise, so the majority of brands dont. Its also now believed to be the more effective compound in the drug as an antidepressant. I believe that the first brand I had bought might have had more of this compound, and the second had none as they were both 0.3% hypericin standardised.
Also Cambridge University are still trying to synthetically manufacture Hrperforin, but a different version that doesnt affect one of the liver enzymes. Due to its effect on the liver, if you only take St Johns Wort there is nothing wrong, and you can pretty much have as much as you like (too much can cause photosensitivity though). But mix it with just about any other drug and you can die. This caused it to be banned in France, and it has to carry health warnings in other countries, but in the UK it doesnt and you can buy it from most health stores.
Also in Germany, they prescribe St Johns Wort as a first line antidepressant before SSRIs, and they have much stricter pharmaceutical standards for extraction there so it is of a more consistent quality unlike health store pills. When used alone it has pretty much zero side effects, and also seems to be one of the only things that can potentially increase dopamine levels in the brain without causing addiction or dependancy. Just got to be careful with those many cross reactions, so even if wanting to use any other OTC drug with it, you need to ask a pharmacist or GP to make sure its safe to do so.
Moderator Action: Deleted sentences about the dosage of SJW to take and whether it is safe for children. That comes closer to being medical advice than we are comfortable with at this site.