What I developed in one of my settings that there are, effectively, infinitely many gods, of varying power levels, one for every distinct thing that there could be a god of. So there is a god of the seas, but also a lesser god of every individual sea, and an even lesser (subsentient or even inert) god of every individual patch of ocean. Objects have 'souls', where souls and gods differ by degrees rather than by kind. This also applies to forces like gravity, as well as every abstract concept a human or other mind has come up with (languages are self-aware entities that influence the minds of those who speak them, for example).

The First Law, which all gods are bound by and which all physical laws derive from, is that a god can not lie, and thus can not break an oath. The most fundamental laws of the universe (relativity, the conservation of energy, a few others), stem from negotiations between the original batch of gods, which embody things to abstract for a human to describe. These laws allowed things to exist in the universe, which in turn created new gods, who made new pacts with each other and their superiors, son on and so forth, from the white-hot plasma of the big bang to the formations of galaxies, stars planets, life, and ultimately sentient life with increasingly complex and varied psychologies and cultures. The physical universe we see is actually an expression of an infinitely complex web of pacts and rivalries between infinitely many gods. It is a weird splice of Shinto animism, Platonic idealism, Social Constructivism, and set theory.

The basis of magic is humans making pacts with these gods/demons/souls. A small number of humans are able to communicate with these entities, most able to do so for only a specific variety of them, like 'true' gods, demons, or inanimate objects. For a few examples:

A deal was made long between a harvest god and the oversouls of certain plant species. Per this deal, these plants must grow on the command of any mortal who bears the blessing of that harvest god. The harvest god grands this blessing to any who A) observe certain rites on a regular basis, B) are 'inducted' by someone who already has the blessing, and C) Never themselves eats any of the food thus created. The "clerics" of the various 'true' gods are created in similar ways.

Certain individuals can communicate with the souls of inanimate objects. A human communicates to the 'soul' of a candle flame. After making a payment of blood (or, more technically, the energy inside the blood, which is valued by certain classes of entities), the fire 'agrees' to continue burning for a time, separate from it's candle. This common binding, called 'Freefire', can be stored in sealed jars and used similarly to light bulbs.

A variation of the theme, say you have wildfire. A man holds his breath and charges into the smoke and sparks head on. The souls of the wildfire, impressed by the mans bravery, offers him a gift, breaking of a portion of it's own soul and grafting it into the man's making him into a Pyromancer.

A Human summons a demon, and binds it to his will. Demons, in this setting, are humanoid creatures who embody and feed on emotions. But no two are exactly the same, because for example, the Demons of Anger are a faction, but each individual member is attuned to a very specific kind of anger, specific enough that there it does not have its own distinct word. Anger at someone you hate, anger at someone you love, anger on someone elses behalf, etc. The demon takes on a physical form for the summoner (possibly requiring subcontracting to various physicaly-aligned object souls to create it), and in exchange he agrees to provoke or lead the demon to a source of the corresponding emotion.