In the Rambam's fourfold division of the subjects one must learn every day comes up Metaphysics.
[This he says over briefly in Mishne Torah but goes into more detail in the Guide. ]
What he says openly in the Guide is that he is referring to the Metaphysics of the ancient Greeks.
Clearly that is a reference to Aristotle's set of books called the "Metaphysics".
But to me this seems to include also Plato, Plotinus, Kant, and Hegel.
That is if you go by the basic subject matter. I know there are a set of great thinkers who were singularly unhappy with Hegel but to me that just makes the whole matter more interesting.
The basic critics of Hegel are: Kierkegaard, Schopenhauer, and Kelley Ross, and Marx and Popper. The questions they ask seem to me to be enlightening but not in the way that they thought. [i.e. they thought they were refuting Hegel but in fact doing a service in making us dig more deeply into what he was saying. People misusing Hegel does not seem to me to be disproof.
As for Physics it is also clear what the Rambam meant. The set of books of Aristotle called "Physics."
To me also it seem necessary to include Quantum Field Theory in this --for the same reason--that I think the Rambam was referring to the subject matter not the specific set of books. [There are a few things one needs to learn along with Quantum Field Theory like Lie Algebras.]
As for the Oral Law the Rambam makes clear in his letter to Yemen that "Just as there is no adding or subtracting from the Written Law so there is no adding or subtracting from the Oral Law." So again it is clear he means the actual set of books the two Talmuds. But also it seems necessary to expand this a little. After all the two Talmuds are are to understand without Tosphot and the Rishonim and a few of the important achronim like Rav Shach and the Pnei Yehoshua.
The Written Law is of course the Five Books of Moses but again it seems necessary to include the rest of the Old Testament along with the explanations of the sages in the several books of Midrash written on it. [e.g. Midrash Raba, Sifrei, Sifra, and few other Midrashim written by the sages of the Talmud.]
[I do not claim to have done this. I got interrupted, and also when I returned to Israel with intent to find a place to sit and learn Torah I was evicted. That has proven to cause a lot of wasted time that I might have just sat and learned in some odd corner away from everyone. [However the time I spent in Netivot was well spent in terms of learning and also I was allowed to sit in there in the Yeshiva of Rav Montag and people were gracious to me. And that also is where I was able to put together my notes on Bava Metzia. Mostly Sephardim learn there but the Rosh Yeshiva in Ashkenazic. In any case, that was a very nice place. It was kind of like the first time I was in Israel up North which also was very nice.] Besides that I do not seem to have the same amount of energy needed to go through the above list that I did have when I was in the Mir. Thus I suggest getting started on that above list as soon as one is able, and not waste time on side stuff that just turns out to be a waste.]
It all seems like a lot to go through but it really is not. All you need to do is to do a half a page a day in order. Just say the words and go on. But it is best to get started already since it does take a few years. No use putting it off.
The way to do this is when you get up in the morning right away to start learning Tosphot. That should be one Tosphot that is reviewed every day for a few weeks. Then some Physics. Page after page. Just say and words in order as fast as possible and go on until you have finished the whole book at least four times. Then if there are still some things that you did not get you can go slower.[Metaphysics is hard to get an idea of what is best there. Hegel seems about the best.]