We know pretty well what matter is and how it interacts with the others.
Dark matter interacts through gravity but not light. Beyond that I haven’t heard much else.
And lastly anti-matter has an opposite charge and interacts with matter through annihilation. I think I remember hearing that it would react with dark matter the same way.
So my question is, does anti-dark matter exist, and what are it’s properties?
Like matter, it doesn’t interact with dark matter to any detectable degree.
I say “doesn’t” on purpose, because we have small containers of the stuff tucked away in labs, and it’s (momentarily) created as an inevitable byproduct of particle accelerators and certain radioactive decays.
Nobody knows what dark matter is beyond it being everywhere and heavy, so double don’t-know. There’s no particular reason to think it would follow a similar pattern, though.