The 15th amendment- The right of citizens of the United States to vote shall not be denied or abridged by the United States or by any state on account of race, color, or previous condition of servitude.
The 19th amendment- Woman Right to Vote
The 24th amendment- added in 1964, prohibits the denial of voting rights for failure to pay a poll tax.
The 26th amendment, added in 1971, changed the voting age to 18 in national elections.