Every Mistress will have at least one foot and leg fetish situation, usually more.
Most will have a combination of ass, tit or pussy worship.
More niche 'physical' fetishes will also appear frequently, like latex and stockings, muscle worship, smothering & facesitting
Every Mistress will have some form of in-depth brainwashing training, whether it's themed more like pet play, slave training, goddess worship, or something else.
Humiliation, strict Mistresses, and gentle ones will all be represented.
Things like pegging, chastity and golden showers will be added after a few updates in expansions to Mistresses that have demand for them.
Total mindfuck/brainwashing and depersonalization is also something I want to add to some of them - really there will be very few limits, I'm just going to give priority to the more common femdom-related fetishes, then sprinkle in the more spicy niche stuff wherever it makes sense.
Also trying to make this more community-driven than a typical project - so if I notice a lot of demand for a particular fetish or type of Mistress, I'll probably implement it at some point.