Oznayim LaTorah on the order of creation of fish-birds-animals-man.
Why did Hashem preserve the original Leviathan to serve the tzadikim in the future rather than serve them a new one?
Ramban/Emet L'Yaakov on why only two humans were created versus many different species of each animal.
How did Matan Torah complete the creation of the Universe?
Chanoch as the only person about whom the Torah doesn't say he died.