Saliva divinorum is inherently dysphoric due to its agonism of the kappa opiod receptor. For a different cheap legal drug that affects serotonin and the NMDA receptors like ibogaine does, there's always off label use of dextromethorphan (cough medicine)!
DXM is also the active ingredient in the antidepressant Auvelity (combined with bupropion)
Lot of interesting studies and anecdotes on its efficacy as an antidepressant
Really difficult to find a cough syrup with only high amounts of DXM and nothing else. All the brands changed their recipes in the late 90s.