Is there a good over-the-counter medication/ointment to help maintain/decrease the appearance and symptoms of plaque psoriasis?

Steroids: Plaque psoriasis usually requires topical steroids for flares. The over the counter steroid creams (cortisone 1%) are not very strong.

Can try cortaid (hydrocortisone): Psoriasis is a chronic autoimmune disease, which affects almost 15 million americans, and most have such minimal disease that they may not even know they have it. A few hundred thousand people have terrible disease with thick plaques on their scalp, hands, feet, and body, and even psoriatic arthritis, you can try some otc drugs, products, with urea, coal tar, and cortisone, but they may not work.