Question

Along with the power to tax, what power has provided much of the basis upon which Congress and the courts have built nearly all the implied powers?

Answer 1

Along with the power to tax, it is the power to do whatever is "necessary and proper" that has provided much of the basis upon which Congress and the courts have built nearly all the implied powers, since this is a very broad statute. 

Answer 2

The answer is the Commerce Clause. Hope i helped.