My three cents.
Whatever one takes the Ultimate to be, by the mere fact of being the Ultimate is necessarily the foundation of all the universe and all reality. That is it.
One does not necessarily have to explain how a certain fact (eg law, being, thing, ..) emerges from the Ultimate, as in principle it cannot but be traced back to the Ultimate itself (by definition of Ultimate).
That is why any philosophy that adheres to some Ultimate does not have to reduce everything conceivable to that Ultimate explicitly in order to be discussed. Being reducible "in principle" is enough for most purposes of philosophical discussion.
That Ultimate may be:
- A personal deity or deities (eg Christian God, Muslim God, ..)
- An principle or principles (eg the Dao, the Brahman, the Geist, the Forms, the Laws, Mind, Matter, ..)
- The sum of everything existing (eg the universe itself)
- so on..
All three candidates for being the Ultimate above, can easily accommodate physical laws (a detailed account of each is outside the scope of this answer).