It's not just filibusters, even. Senators can also issue "secret" holds. At one point, Jeff Sessions (R-AL) put a hold on every single nominee simultaneously un

It's not just filibusters, even. Senators can also issue "secret" holds. At one point, Jeff Sessions (R-AL) put a hold on every single nominee simultaneously until some pork was added to a defense spending bill. These holds have been common practice and they are very rarely publicized.