There is a website called f95zone.to, which is dedicated to independently developed porn games.
Free Cities is a management style game, where you play as the primary stockholder of a private city, where sex slavery is legal. In it, you can assign slaves to various roles, including prostitution, gladiatrix, and hucows, as well as domme roles, such as madam, head girl, and prison warden. You can assign a slave to slave labor, but that part of the game is glossed over completely, essentially writing the slave out of the game when you do so.
Stationmaster is a game made in unity. It is heavily based on Free Cities, but is a lot more detailed and uses 3D graphics. It uses a lot of the same mechanics as Free Cities, but where you are the owner of a privately owned space station, which you can expand into a galactic empire and conquer planets.
I also hoped to make a game about slave labor. I only imagine making a command-line game, but I might eventually complete something.
I also think about an online roleplaying game or community, similar to what have been described within this thread in Second Life, but where users will vote to subjugate a part of the population, and the members of the community, who fit that category, will be enslaved within the game. It can be either male, female, or both, depending on what has been voted, and the nature of the subjugation will be entirely vote driven.