Yrazul is in the process of being converted to D&D 5th edition from D&D 3.5 Edition, with some house rules for character advancement, and restrictions upon allowed classes and races. See the appropriate section for details.
GMLibrary - the are the 5th edition books I own, from which I've drawn the most of the rules we use.
Permitted Races - these are the permitted PC races.
Permitted Classes - these are the permitted PC base classes.