Delphi: At runtime find classes that descend from a given base class?

Is there at way, at runtime, to find all classes that descend from a particular base class?

For example, pretend there is a class:

TLocalization = class(TObject)
...
public
   function GetLanguageName: string;
end;

or pretend there is a class:

TTestCase = class(TObject)
...
public
   procedure Run; virtual;
end;

or pretend there is a class:

TPlugIn = class(TObject)
...
public
   procedure Execute; virtual;
end;

or pretend there is a class:

TTheClassImInterestedIn = class(TObject)
...
public
   procedure Something;
end;

At runtime i want to find all classes that descend from TTestCase so that i may do stuff with them.

Can the RTTI be queried for such information?

Alternatively: Is there a way in Delphi to walk every class? i can then simply call:

RunClass: TClass;

if (RunClass is TTestCase) then
begin
   TTestCase(RunClass).Something;
end;

See also

• Finding all classes that derive from a given base class in python
• Java: At runtime, find all classes in app that extend a base class