Principles of NMR
A classic online text is Joseph Hornack’s Basics of NMR.
Paul Callaghan’s lectures provide an excellent introduction to the physics of magnetic resonance.
Introductory NMR &MRI by Sir Paul Callaghan
The NMR periodic table shows which elements are suitable for NMR experiments.
Here is the version of Rider University:
A. Jerschow’s version of ordering NMR active elements is also interesting:
There are several software packages, which allow the prediction of NMR spectra.
NMRDB (FCT-Universidade NOVA de Lisboa ) is a free and can be used directly from a web browser.