Chad’s Coursesaver - the lectures are great and targeted towards the DAT specifically. It also has practice questions with explanations after every section for practice.
Other than that - free ones are everywhere
YouTube is great
Crashcourse for when you need some relaxing review while you eat
Khan academy/The Organic Chemistry Tutor when you need extra practice and explanation
Cliffs - free bio book
Feralis notes
I guess what I’m saying is that if you have the time, don’t limit yourself!