All the C# knowledge you could ever ask for
In all seriousness, like Chronos said, there is no single link. I've been using C# for around 6 years now and I've barely scratched the surface of "C#" despite covering more or less the entirety of the syntax. C#, like many well-designed languages, can be used for so many different things, and as a result "most knowledge" is a bad attribute to look for. What you want is the most information for a specific topic, and in that case Google is where you want to start looking. You'll get links to source examples, StackOverflow, MSDN and more, and it's only when you enter queries about what you're actually looking for that you get the knowledge you seek, and you generally (I say this because I've worked with some things that have very little coverage given how obscure they are) will find it.
If you have no experience or knowledge of C# whatsoever, but have some programming understanding, I would go here: https://msdn.microsoft.com/en-us/library/67ef8sbd.aspx
Pretty sure given your question that you do not, so instead I'd probably look here: https://mva.microsoft.com/en-US/training-courses/c-fundamentals-for-absolute-beginners-16169?l=Lvld4EQIC_2706218949
Really even after all of this you need to be researching object oriented theory and building your understanding of what it is, how it works, and why it works. Just understanding how to write simple inheritance doesn't really mean you understand inheritance, or how to make the best use of it.
Programming is a beast. It's not a beast to fear, but there's no singular resource, just like there's no singular compendium of knowledge for any difficult and rapidly evolving field.