There are herbs available that are potent and that do stimulate ovulation, but they are not as powerful as Clomid and my suggestion would be not to expect miracles, and of course to consult your doctor or at least herbalist and not to experiment on your own. When a person is taking herbs (or medicines) the underlying cause matters, right? There is a reason woman does not ovulate and this reason must be known it is important to treat the cause and not only the consequence, which is actually what Clomid does it treats lack of ovulation. Also there are herbs that should be avoided if woman is trying to conceive or already pregnant. As already said, there are herbs available that stimulate ovulation.
Some of them are wild yam and vitex. But it is essential to consult with herbalist, because taking herbal supplements without prior consultation could make the situation worse. Let me explain why. Both wild yam and vitex do encourage ovulation but only if woman has the imbalance also know as kidney yang vacuity. This imbalance includes low progesterone levels as well as luteal phase defect and in cases like this there herbs could be helpful. But lack of ovulation could occur because woman has deficient levels of estrogen (which is according to Chinese traditional medicine low in yin energies, resulting in hot flashes, night sweats, dry eyes, mouth, vagina, lack of cervical mucus etc.) and in this case taking wild yam or vitex supplements would make the situation worse. Some herbalist would recommend herbs like angelica and asparagi to restore reproductive balance in this scenario.