More specific "Find usages" variants

I find the Find Usages function to be very useful, and I use it a lot. However, I think it could be even more useful if it were possible to do some more specific searches rather than to always find all usages. For instance, I would like to:

• When used on a class name, find all places where a subclass is declared
• When used on a class name, find all places where an instance is created
• When used on a constructor, find all places where this constructor is used
• When used on a variable, find all places where the variable is assigned