For your FIT prep in particular:
On top of the insights already shared in the post, the "Integrated FIT guide for MBB" has been recently published in PrepLounge´s shop (https://www.preplounge.com/en/shop/tests-2/integrated-fit-guide-for-mbb-34)
It provides an end-to-end preparation for all three MBB interviews, tackling each firms particularities and combining key concepts review and a hands-on methodology. Following the book, the candidate will prepare his/her stories by practicing with over 50 real questions and leveraging special frameworks and worksheets that guide step-by-step, developed by the author and her experience as a Master in Management professor and coach. Finally, as further guidance, the guide encompasses over 20 examples from real candidates.
Feel free to PM me for disccount codes, since we still have some left from the launch!
Hope you find it useful!