There are, at the moment, three issuers of PIN-preferred cards in the United States: United Nations Federal Credit Union, First Tech Federal Credit Union, and Harvard University Employees Federal Credit Union. The first two anyone can join by first becoming a member of a particular nonprofit association. Given a choice, I would go for First Tech (or the Harvard Alumni card if you qualify) since they offer no foreign transaction fees and support all PIN variations (where the PIN can either be verified by the card itself or over the network by the bank); UNFCU only offers no foreign transaction fees on a card with an annual fee (you'd have to decide for yourself if the annual fee is worth the other additional benefits).
There is one other PIN-preferred option, the Diners Club MasterCards issued by BMO Harris Bank. However, they stopped taking applications several months ago and haven't resumed, so they're not an option at present if you don't already have it.
Two other fairly large issuers, USAA and Navy Federal Credit Union, were offering PIN-preferring cards but switched to Signature preferring.
But one question to consider is if you need a PIN-preferring card, or merely one that supports PIN? In the latter case, you'll still sign most of the time but if you encounter a situation where a PIN is required, it will work. Bank of America, Citibank, Wells Fargo, and Synchrony Bank (they issue a lot of affiliate branded cards like Walmart and Banana Republic) all fall into this category. A PIN preferring card would allow you to more easily blend in in Europe, but for now would actually be harder to use in the US; particularly in restaurants since even those that have switched to EMV card readers are still doing the thing where they take your card away from the table, so you'd end up having to go with them to wherever they have the terminal set up to enter your PIN, rather than being like Europe and Canada where the waiter has a portable credit card reader that they bring to your table.