Here is the guide to the use of Wizards of the Coast intellectual property:
Two parts that are most interesting to you are:
Can I use all of Wizards’ IP?
Unfortunately, no. You cannot incorporate Wizards patents, game mechanics (unless your Fan Content is created under the D&D Open Game License), ...
Sure there is—pay Wizards of the Coast to license that material.
The Open Game License is free, but only covers a subset of the game. Often it covers just one example of each kind of thing. In order to include the rest of the content, you need to license it from Wizards of the Coast—but they don’t offer it under the Open Game License, so you’ll have to get ...