The United States Mint <https://www.usmint.gov> produces these collector sets annually. There are important differences between the sets.
Proof vs. uncirculated coins
Proof coins are a type of strike, not a grade. Both blanks and dies are polished, they are hand fed for minting and struck at least twice. Mint coins are Uncirculated examples of each coin minted, or produced, that year. They are also referred to as a Business Strike.
Proof sets are the longest-running series produced by the U. S. Mint. The first Proof coin produced was the 1831 half-cent and 1936 saw the first sets, which included the cent, nickel, dime, quarter and half-dollar. In 1942 a second set was produced including the silver “War Nickel.” Proof sets were minted (without a mint mark) in Philadelphia through 1964, and San Francisco began production in 1968 bearing the “S” mint mark.
The Eisenhower Dollar was added to the sets in 1973. 1975 featured Bicentennial coins bearing 1776-1976 dating on the quarter, half-dollar and dollar.
The smaller Susan B. Anthony dollar coin was introduced in 1979.
The 50 State Quarters series began in 1999, and each year’s 5 coins were added to the sets. The golden colored Sacagawea Dollar was added in 2000.
Westward Journey series Nickels (2) were featured in sets in 2004-2005. The Presidential Dollar coin series started in 2007. The Lincoln Bicentennial cents were added, featuring a return to 95% copper composition of those coins. In 2010 the America the Beautiful Quarters and Presidential Dollars began to be sold separately from the standard Proof set.
90% Silver Proof Sets have been available since 1992, and featured the 5 State Quarters starting in 1999. The packaging has a different color scheme (red 1992-2009; black and silver currently.)
The U.S. Mint (San Francisco) produces subsets to the Proof sets, such as 50 State Quarters (Silver or Clad), America the Beautiful (Silver or Clad), District of Columbia and U. S. Territories Proof Sets, and the Presidential $1 (2007-2016.) Prestige Proof sets were sold from 1983-1997 (except 1985.) They feature the year’s Commemorative Dollar Coin and Half Dollar in special premium packaging.
For Grading purposes, when the field and the design have significant contrast it is designated Cameo, and if it has further contrast it is designated Deep Cameo. The Grading firms identify them on their slabs as CAM and DCAM (PCGS); CAM and ULTRA CAM (NGC). Proof coins with any wear are called Impaired Proof.
Mint sets represent Uncirculated examples of the business strike coins intended for general circulation that year. The Denver mint makes coins designated with a “D” and the Philadelphia mint makes coins designated with a “P.” Of note, cents minted at the Philadelphia mint have no mintmark.