Harvard, Princeton, Yale & Stanford all offer SCEA (Single Choice Early Action), although Princeton will not offer any early option this year.
I think of REA as a slightly different twist, and confess that I have lost track of the distinctions among Georgetown, Notre Dame, and whatever BC used to offer. I believe that student used to be able to apply to all three as REA apps, whereas that would not be the case with SCEA at HYPS.