Are there any books about MO theory that explain the theory to a certain detail but don't rely on a lot of math background or explain the math within the book?
I'd suggest the seminal Orbital Interactions in Chemistry by Albright, Burdett and Myung-Hwan Whangbo.
The second edition came out in 2013 and I'm sure there are many copies of the first edition around as well.
They focus a lot on pictoral MO theory - indicating how orbitals of different shapes and symmetry combine.
To truly understand MO theory at a fundamental level, it really helps to study some quantum mechanics (and thus mathematics) but you can grasp a lot from the approach used in this book.