Here is a list of all 30 enumerated powers

One of the things that makes the U.S. Constitution superior to all others is that it limits the powers of Congress.  In other words, Congress only has the power to make laws regarding items specifically listed in the Constitution.  These powers are generally referred to as enumerated powers.

Many of these powers are listed in Article I, Section 8, of the Constitution, and many others are listed in the Bill of Rights, among the other 17 amendments, or scattered elsewhere throughout the Constitution.  Overall, there are only 30 enumerated powers, or only 30 areas in which Congress has the power to act upon (it may be 35, depending on how they're counted).

We also must regard the 10th amendment here.  It says: "The powers not delegated to the United States by the Constitution, nor prohibited by it to the states, are reserved to the states respectively, or to the people."  What this means is that if it is not covered among the enumerated powers (i.e. marriage, abortion, Internet, education, etc.) Congress has no legal right to rule on it, and if it does, then the U.S. Supreme Court shall overturn it.

Here is a list of all 30 of the enumerated powers.  This list is from the tenthamendmentcenter.com, although it can be found in pretty much any book covering the U.S. Constitution, including the Constitution itself. .

1. To lay and collect Taxes, Duties, Imposts and Excises, to pay the Debts and provide for the common Defence and general Welfare of the United States; but all Duties, Imposts and Excises shall be uniform throughout the United States;
2. To borrow Money on the credit of the United States;
3. To regulate Commerce with foreign Nations, and among the several States, and with the Indian Tribes;
4. To establish an uniform Rule of Naturalization, and uniform Laws on the subject of Bankruptcies throughout the United States;
5. To coin Money, regulate the Value thereof, and of foreign Coin, and fix the Standard of Weights and Measures;
6. To provide for the Punishment of counterfeiting the Securities and current Coin of the United States;
7. To establish Post Offices and post Roads;
8. To promote the Progress of Science and useful Arts, by securing for limited Times to Authors and Inventors the exclusive Right to their respective Writings and Discoveries;
9. To constitute Tribunals inferior to the supreme Court;
10. To define and punish Piracies and Felonies committed on the high Seas, and Offences against the Law of Nations;
11. To declare War, grant Letters of Marque and Reprisal, and make Rules concerning Captures on Land and Water;
12. To raise and support Armies, but no Appropriation of Money to that Use shall be for a longer Term than two Years;
13. To provide and maintain a Navy;
14. To make Rules for the Government and Regulation of the land and naval Forces;
15. To provide for calling forth the Militia to execute the Laws of the Union, suppress Insurrections and repel Invasions;
16. To provide for organizing, arming, and disciplining, the Militia, and for governing such Part of them as may be employed in the Service of the United States, reserving to the States respectively, the Appointment of the Officers, and the Authority of training the Militia according to the discipline prescribed by Congress;
17. To exercise exclusive Legislation in all Cases whatsoever, over such District (not exceeding ten Miles square) as may, by Cession of particular States, and the Acceptance of Congress, become the Seat of the Government of the United States, and to exercise like Authority over all Places purchased by the Consent of the Legislature of the State in which the Same shall be, for the Erection of Forts, Magazines, Arsenals, dock-Yards, and other needful Buildings; And
18. To make all Laws which shall be necessary and proper for carrying into Execution the foregoing Powers, and all other Powers vested by this Constitution in the Government of the United States, or in any Department or Officer thereof.
19. No State shall, without the Consent of the Congress, lay any Imposts or Duties on Imports or Exports, except what may be absolutely necessary for executing it’s inspection Laws:and the net Produce of all Duties and Imposts, laid by any State on Imports or Exports, shall be for the Use of the Treasury of the United States; and all such Laws shall be subject to the Revision and Controul of the Congress.
20. The Congress may determine the Time of chusing the Electors, and the Day on which they shall give their Votes; which Day shall be the same throughout the United States.
21. In Case of the Removal of the President from Office, or of his Death, Resignation, or Inability to discharge the Powers and Duties of the said Office, the Same shall devolve on the Vice President, and the Congress may by Law provide for the Case of Removal, Death, Resignation or Inability, both of the President and Vice President, declaring what Officer shall then act as President, and such Officer shall act accordingly, until the Disability be removed, or a President shall be elected.
22. The judicial Power of the United States, shall be vested in one supreme Court, and in such inferior Courts as the Congress may from time to time ordain and establish.
23. The Trial of all Crimes, except in Cases of Impeachment, shall be by Jury; and such Trial shall be held in the State where the said Crimes shall have been committed; but when not committed within any State, the Trial shall be at such Place or Places as the Congress may by Law have directed.
24. The Congress shall have Power to declare the Punishment of Treason, but no Attainder of Treason shall work Corruption of Blood, or Forfeiture except during the Life of the Person attainted.
25. Full Faith and Credit shall be given in each State to the public Acts, Records, and judicial Proceedings of every other State. And the Congress may by general Laws prescribe the Manner in which such Acts, Records, and Proceedings shall be proved, and the Effect thereof.
26. New States may be admitted by the Congress into this Union;
27. The Congress shall have Power to dispose of and make all needful Rules and Regulations respecting the Territory or other Property belonging to the United States; and nothing in this Constitution shall be so construed as to Prejudice any Claims of the United States, or of any particular State.
28. The Congress, whenever two thirds of both Houses shall deem it necessary, shall propose Amendments to this Constitution, or, on the Application of the Legislatures of two thirds of the several States, shall call a Convention for proposing Amendments, which, in either Case, shall be valid to all Intents and Purposes, as Part of this Constitution, when ratified by the Legislatures of three fourths of the several States, or by Conventions in three fourths thereof, as the one or the other Mode of Ratification may be proposed by the Congress
29. The House of Representatives shall chuse their Speaker and other Officers; and shall have the sole Power of Impeachment…
    The Senate shall have the sole Power to try all Impeachments. When sitting for that Purpose, they shall be on Oath or Affirmation. When the President of the United States is tried, the Chief Justice shall preside: And no Person shall be convicted without the Concurrence of two thirds of the Members present.
30. The Times, Places and Manner of holding Elections for Senators and Representatives, shall be prescribed in each State by the Legislature thereof; but the Congress may at any time by Law make or alter such Regulations, except as to the Places of chusing Senators.