If I were to say, "I have anything". what would I be saying? Also I have seen one question about anything vs nothing. What about anything vs everything? I also have a question about what seems to be a contradiction of sense and reference when asking this same question negatively. i.e. I don't have anything
You don't say "I have anything", it doesn't have a real meaning.
You can say "I can have anything", or "I don't have anything". You can say as a question "Do I have anything?" But there is no meaning to "I have anything".
If you have an object it is no longer "any thing". It is now a particular thing, it is the thing that you have. If you have it, is becomes a "something". So you can say "I have something". So it is grammatically correct to say "I have anything" but the meaning doesn't work.