Kinds
The concept of a kind (type, category, etc.) of something is often omitted in Toki Pona. If something is a kind of x, it can often simply be described as x.
There are several words that can help express this concept explicitly when needed. kulupu describes a group of things, so one phrasing could be lon kulupu (lit. 'in a group'). nasin describes ways, including a way of being or doing. sama describes similarities, and can be used as a modifier for similar things, groups of like things (kulupu sama), and things of the same way or method (nasin sama).
Some speakers use extended senses of kule and poki to refer to intrinsic and extrinsic properties.
There are also dedicated nimi sin that have been created to mean "kind", but they tend to be obscure and scarcely used.