I will search and post as many names as I can.
First I need some definitions though..
For Scientists, we are looking for : Mathematicians, Geometers, Astronomers... anything else in this category?
For Prophets, we are looking for : Prophets obviously, Saints and Apostles for Christians, Oracles for Greco-Romans (?) what else ?
For Engineers , we are looking for : Architects I guess, and Engineers that were constructing siege weapons and fortresses during wars.. anything else?
For Merchants, we are looking for : Merchants (I doubt we will find someone similar to Marco Polo..) and Explorers.
For Artists, we are looking for : Poets, Philosophers, Historians, Play Writers, Sculptors... anything else?