During E3 2006, Nintendo introduced the Classic Controller, which plugs into the Wii Remote via a cord in a similar fashion as the Nunchuk. The overall configuration is similar to that of other major seventh generation console controllers, and is also particularly similar to the SNES controller.
The Classic Controller features two analog sticks, a D-pad, a, b, x and y buttons, the L and R shoulder buttons, and two Z buttons (labeled ZL and ZR) next to the L and R buttons, respectively. It also has a set of -, Home, and + buttons like those on the Wii Remote.
In 2009, Nintendo released a revision of the Classic Controller named the Classic Controller Pro, with a new wing grip design and the ZL and ZR buttons relocated behind the L and R buttons as secondary shoulder buttons, in the vein of the Z button on the GameCube controller. As it was released after Brawl, the game makes no reference to the new model; all images show the original Classic Controller. However, the controller is fully compatible with Brawl, and is considered superior to its original counterpart by competitive players.
3rd party controller manufacturer PDP, with official licensing from Nintendo, released a "Wired Fight Pad" controller in November 2014, a Classic Controller whose control layout has been redesigned to strongly emulate the look and feel of a GameCube controller. However, its technical workings are just like any other Classic Controller and as such it connects to the console wirelessly by plugging into the Wii Remote. Owing to its design and release date, some players presume that it is targeted primarily towards Smash Bros. players. Another GameCube controller-shaped Classic Controller exists on the market, the Hori Battle Pad, which is much closer to the GameCube controller than the PDP Fight Pad. 
Despite its similarity to the GameCube controller, it is not compatible with GameCube games because it does not plug into a GameCube controller port by default, and as such cannot be used to play Super Smash Bros. Melee.
In the Super Smash Bros. series
In Super Smash Bros. Brawl and Super Smash Bros. for Wii U, the Classic Controller can be used as a viable control scheme, along with the standalone Wii Remote, the Wii Remote and Nunchuk combination, and the GameCube controller.
Super Smash Bros. Brawl and Super Smash Bros. for Wii U
Super Smash Bros.
|Nothing||Home Menu/Operations guide|
|Nothing||Move (menu only)|
In competitive play
Although the GameCube controller was competitive Brawl's most popular controller option, the Classic Controller, specifically the Classic Controller Pro, was significantly popular as well. Its ease of access at the time of release as well as being shaped the most like an industry standard controller made it attractive to new players. Derivatives like the Hori Battle Pad were also relatively popular due to being directly modeled after a GameCube controller. The Virtual Console release of Super Smash Bros. also enticed Smash 64 players that skipped Melee to use the controller by bridging the gap between the games.
Despite also being available with Super Smash Bros. for Wii U, its direct successor, the Wii U Pro Controller, being compatible with the same game, made it quickly fall out of favor and become a rarity in tournaments for that game.
|Controllers and buttons|
|Nintendo 64 controller|
|Wii Remote (and Nunchuk)|
|Wii U GamePad / Pro Controller||LR|
|Switch Pro Controller||LR|
|Third-party controllers||Hori Mini Pad · Arcade controller · Keyboard|