For example, I need list of users.
In another, I need this list to start to add an empty element (for select)
This is generally to receive the data is not relevant, how you use the data is irrelevant to the API.
Third, we need a list with the additional condition, say, all users with flag enable = 1
and so forth.
If you are talking about internal API is the same in General:
$Users->search(['enabled' => 1])
If parameters can be a small amount - you can just make each option a separate argument if the data is large - the filter which columns to return can also be put in a separate argument, but it is necessary to know what you have how and of what scale.
Most importantly make the operation atomic, then you can compose as needed.