It is difficult to provide a definitive answer to this question, as the risk of teratogenic effects depends on many factors, including the dose, frequency, and timing of exposure, as well as individual differences in susceptibility.
That being said, substances that are generally considered low-risk teratogens include caffeine, acetaminophen (Tylenol), and some antibiotics (such as penicillin and amoxicillin). However, it is important to note that even substances with a low risk of teratogenic effects should only be taken during pregnancy under the guidance of a healthcare provider.