The Rock is a deck which has been less defined by the cards it uses and more by the strategy it employs. In general it is a black-green aggro-control deck which attempts to generate card advantage over longer periods of time and finish the opponent off with a big creature. The cards used for each specific role have varied over the years the deck has existed.
The Rock and his Millions
The Rock was originally a Type 2 Deck around the Urza Block designed by Sol Malka. It used Birds of Paradise and Llanowar Elves to get early mana development going and generate Card Advantage with Yavimaya Granger and Yavimaya Elder. In the end the game should be finished by Phyrexian Plaguelord and Deranged Hermit, "The Rock" (Nicknamed for professional wrestler Dwayne "The Rock" Johnson) clearing the board with "his millions" (tokens). Overtime it has become common for Phyrexian Plaguelord to be thought of as "The Rock" however this is a misconception.
Ice Age-Invasion Extended
The deck was later adapted for extended and while holding true to the original concept and retaining much of the cards, it moved gradually away from the original intent as it got rid of Deranged Hermit and also used less and less Plaguelords. The biggest shift happened when Apocalypse brought Pernicious Deed and Spiritmonger. At the end of the lifecycle of that rotation, Michael Pustilnik won a Grand Prix with this build:
In the following years, the deck saw a few alterations of its core, especially as green fatties became cheaper. Ravenous Baloth, Cabal Therapy and Eternal Witness were immediately adopted when they first became tournament legal.
Ravnica Block brought a new revolution upon The Rock as the new Dual lands not only made the mana basis of the deck even more stable but also made it much easier to splash other colors. Rock decks which splashed White for Loxodon Hierarch and Mortify, red for Flametongue Kavu and Terminate or blue for Gifts Ungiven were no rarity and some decks even splashed multiple additional colors.
Most recently split off in two camps, decks that utilize Death Cloud and decks that splash white. Although there is only limited overlap between both decks, they are both fueled by Life from the Loam and their similarities in how to play them can easily be observed.