NFA to DFA question

First, this is not a question asking for the algorithm to convert a NFA to DFA.

It's known (and proved) that the equivalent DFA of a NFA has at most 2ⁿ states, even though most of the times it will have more or less the same number of states as the NFA.

How may I predict an estimate for the number of states the NFA-equivalent DFA will have? Which particular type of NFA will require an equivalent DFA to have 2ⁿ states?

My reason for asking this is to be able to "invent" some NFAs that will certainly produce, without considering minimization, 2ⁿ - 1 states plus the "dead state".