In front of the Museum of the City of Skopje several mainly Roman gravestones are on display. Several of them contain reliefs with lots of details, from the head of the interred, a man on a horse to various objects and fruits. If you don't have the time to visit the museum, examine at least the interesting reliefs. Unfortunately, the condition of them is not at its best and they have again to face the weather, but maybe one day they are going to be restored and displayed protected from the weather.
Further information on some of them can be found at lupa.at/museums/550