Ontology is the study of being. Yeah, anyway, here are some ideas:
1: Monism: only one thing "exists".
2: Dualistic paradigm: existence vs non-existence. These terms are not further defined
3: Dualistic paradigm: physical vs metaphysical (which means "beyond the physical").
3.1: Physical is defined as "what is made of matter", whereas metaphysical is something that is not made of matter. Examples of physical things: chairs, rocks, rivers, clouds, alcoholic beverages, mountains etc. metaphysical objects may include numbers, abstract concepts, country borders, consciousness, light, electromagnetic radiation in general, temperature and gravity.
3.2: Same as above except that what interacts directly with physical objects is also considered physical. So, unlike in 3.1, light, electromagnetic radiation in general, temperature and gravity are considered physical.
4: Same as 3.2. but what is considered metaphysical in 3.1 and physical in 3.2 (light, electromagnetic radiation, temperature and gravity) is considered "transphysical" here, so there are three ontological categories here: physical, transphysical and metaphysical
5: Sensorial vs non-sensorial. Sensorial is what is perceived by "the five senses", and non-sensorial is what is not. Examples of sensorial objects are: chairs, rocks, rivers, clouds, alcoholic beverages, mountains etc. whereas non-sensorial objects may include numbers, abstract concepts, country borders, non-visible electromagnetic radiaton etc. temperature may be considered sensorial because, even though it's not perceived by the common definitions of "the five senses", it is still sensorial because it is sensed by what is called "thermoception". In some interpretations, one can say that one senses temperature through touch, and so, it can be easily argued that temperature is sensorial. Light is more ambiguous, because one can either say that one senses light through the sense of sight, or that one does not sense light itself, but only the objects that are made visible by light. In any case, with my clever method, it's always possible to "solve" these problems. Look:
5.1: Light is sensorial because one can sense it through sight
5.2: Light is non-sensorial because what one senses through sight is not light itself, bur rather, the object(s) made visible by light.
This is how it's done, lmao