EndNETBlock[] and a preceding BeginNETBlock are equivalent to the NETBlock function, except that they work across a larger span than the evaluation of a single expression.
GetActiveCOMObject[string] acquires an already-running COM object specified by string, which can be either a ProgID (such as "Excel.Application") or a CLSID (such as ...
GetComplexType[] returns the .NET type that is currently mapped to Mathematica Complex numbers.
GetNETException[] returns the .NET exception object that was thrown in the most recent call from Mathematica to .NET.
LoadedNETAssemblies[] returns a list of all the .NET assemblies that have been loaded into the current session.
LoadedNETObjects[] returns a list of all the .NET objects that have been loaded into the current session.
LoadedNETTypes[] returns a list of all the .NET types that have been loaded into the current session.
NETLink[] returns the MathLink LinkObject that is used to communicate with the .NET/Link .NET runtime.
NETObjectQ[expr] gives True if expr is a valid reference to a .NET object, and False otherwise.
SameObjectQ[object_1, object_2] returns True if and only if the NETObject expressions object_1 and object_2 refer to the same .NET object.