Some helpful interview topics (Differences X VS Y)

IEnumrable VS IEnumarator 

IEnumrable VS IQueryable 

IEquatable VS IEqualityComparer VS IStructuralEquatable 
IComparable VS IComparer VS IStructuralComparable 

Delegates VS Events

Covariance vs ContraVaraince - http://www.c-sharpcorner.com/UploadFile/hasansheik/covariance-and-contravariance-in-C-Sharp/

Shadowing VS Overriding

Yield

Abstraction VS Encapsulation

Lambda expressions , Action , Func and Predicate

Generics

IOC & Dependancy Injection

async, await

MVVM, MVC, MVP

TPL

Indexer

Private Constructor

Private Class

Static Class VS Singleton
Culture and UICulture
LINQ: Single vs. First
a.Equals(b) and a == b?
SQL XML - CROSS APPLY V/S OUTER APPLY
Null values are in Sub query...
Diffrence Int32.parse, Convert.ToInt32, Int32.TryParse
Perform shallow copy of an object VS Deep Copy