My character builder seems to not be giving me all the race and class options I have access to, based on the sources in my library ...

For instance, it doesn't list Chronurgy Magic or Graviturgy Magic as Arcane Traditions I can choose for a Wizard. Similarly, I only have options of 4 subraces of Elves, despite seeing all the others when I click on "view >>>> page." 

Any wisdom from the hive mind?

On the “Home” tab of the character builder, the toggles next to “Critical Role Content,” “Eberron content,” and “Magic: the Gathering content” need to be on (red, to the right) or you won’t see things from Wildmount, Eberron, or Theros and Ravnica.

Yup. Done that. Still not showing. So weird.

Have you purchased those books from this website? (Those will only show if you have.) If so, then please follow this link and make sure that your “entitlements” are “synced.” (Fancy way of saying that you are being granted access to everything you are supposed to be able to access.) If it offers you a chance to re-sync, then do that.