Free Cities, Pytfall(although focuses more on rpg elements over slavery atm), whoremaster (use crazys mod) to name a few. IMO though, free cities and strive will be your best bet. Pytfall feels the most similar to strive. Yet entirely different. Whoremaster is very old, and I havent played it in a very long time, but crazys mod just got updated not long ago, maybe worth a shot. Personally I enjoy them all to some extent.