Weed or synthetics is an obvious option.
I'd approach ritalin with care - it might end up destabilizing your moods, or not doing much for you because of all the other meds you're on (i'm particularly looking at the seroquel).
Ketamine might be an option, at least used in moderation. It shouldn't interact with anything else you're on, though the seroquel might block it. K is also being investigated as a treatment for depression, and I think also bipolar disorder, so i think we can give it a green-light from the mental health side as well.
Psychedelics are also an option that should be safe. I would avoid mushrooms and 4-AcO-DMT, because it sounds like you're susceptible to seizures, and shrooms/4-AcO-DMT can trigger seizures (it's a very rare side-effect, but seeing as you're on medication to prevent seizures), i would avoid them for good measure