Black saddles and black bar tape. Other colors may work on a given build, but black always works on any build.
Campagnolo Nuovo Record rear derailleur. There were and are better performing RDs out there, but the NR is perhaps the most iconic, coolest looking component ever sold.
Brooks Pro, Brooks B17, or San Marco Rolls saddle.
Campy 2-bolt seat post.
Phil Wood hubs, at least for any freewheel build (as opposed to a free hub build).