Chestnut is a great reference.
But as others have said there are only a few fairly unique to OB that you might be asked to give: oxytocin (a.k.a. Pitocin, Syntocin or some similar sounding name in Europe), Methergine (methylergonovine), Hemabate (prostaglandin F2alpha).
Additionally OB may use misoprostol (Cytotec) or dinoprostone (Cervidil). Misoprostol can be used for both cervical ripening as well as a uterotonic.
Labetalol, hydralazine, and magnesium sulfate are the most common drugs used in preeclampsia. Occasionally they may go to nicardipine. But all these drugs are used outside of OB also.
Nitroglycerin (SL spray or IV, personally I prefer IV) or more commonly terbutaline (IM -- a.k.a. Brethine) for acute tocolysis. I haven't really seen terbutaline used anywhere else, but it's just a beta agonist. NTG obviously is used outside of OB also.
Then there are your neuraxial local anesthetics and narcotics, but again these are used outside of OB also. Except maybe chloroprocaine -- I've only used that in OB. In OB the locals are usually lidocaine, chloroprocaine, ropivacaine, or bupivacaine. The neuraxial narcotics are usually fentanyl, sufentanil, or morphine. Parenteral narcotics tends to be morphine, meperidine, fentanyl, remifentanil, and your mixed agonist-antagonists (Nubain and Stadol).
Then there are your antiemetic agents and aspiration prophylaxis agents, the most common of which is Bicitra (sodium citrate). While Bicitra is most commonly used in OB, this is obviously not exclusive.
Then there are your standard IV induction agents, muscle relaxants, and inhalational agents. But nothing unique to OB.
I think that's a fairly exhaustive list for my post-call brain. Did I miss anything?