For preparation I used CBT Nuggets ITIL Foundation Course(by Chris Ward) and Live Lessons ITIL Foundation Exam Course(by Jill Knapp).
I also make some study notes while watching videos which helps me to understand better.
I also used dumps just for test my knowledge NOT for actual exam.
If you are going for exam I'll prefer these two courses to must watch. First go with CBT Nuggets then with Live Lessons ITIL Foundation series. After watching these two courses you'll no need to watch any other tutorials or any book.
All questions was from dumps I have attached.
All the Best