The go to book is Lindeburg, linked below.
But I also highly recommend ordering an ncees practice test, was on the fence about it until a few a before and finally did. Don't think I would have passed without it.
PPI FE Other Disciplines Review Manual – A Comprehensive Review Guide to Pass the NCEES FE Exam https://www.amazon.com/dp/159126443X/ref=cm_sw_r_awdo_HV4VDKMM53D1JBK77X96
I "used" the FE Other Disciplines Review by Lindeburg
I say "used" because I probably went over 7 out of the 60 something sections in the book.
Major is Petroleum engineering, and I graduate in December.
For me there was a ton of structural stuff. Finding how much load something has. I had zero idea how to do those. Also a lot of problems could be passed with just F=ma. Quite a few electricity problems too. Parallel series especially.
Finding equations with the book is pretty easy if you know who to use the find function.
I'm looking at the used versions.
As well, is the FERM a good idea as well? By that I meant the overall FE manual without disciplines. I think that's what it is anyhow