There's a lot of assertions that I throw into business applications that would be very useful to test in this way. So I don't think this only applies to testing databases.

Also, when properties are difficult to think of, that often means that a model of the behavior might be more appropriate to test against, e.g. https://concerningquality.com/model-based-testing/. It would take a bit of design work to get this to play nicely with the Antithesis approach, but it's definitely doable.