Gallery is a mode in Super Smash Bros. Melee, Super Smash Bros. Brawl and Super Smash Bros. 4 under the Trophy section of the games, where players can view individual trophies. In addition, players can view flavour text about the trophy, access a list that shows the player what trophies they have, and see how many of each trophy they own.
In Super Smash Bros. Melee
When viewing individual trophies, the player can read flavour text about the subject of the trophy, as well as what game it first appeared in, when that game came out, and, exclusive to the Japanese language, what month and year the game was released.
From there, the player can press the A button to enter a viewing mode; in this mode, the player can zoom in and out on the trophy, as well as change the background lighting.
Pressing the B button sends the player to a checklist of sorts, showing all the trophies collected, and the cumulative count of how many of a trophy they have. Additionally, players have the ability to arrange this checklist by three ways: "Normal", "Game" (which arranges them by universe of origin), and "A-Z" (which arranges them by name).
As an added Easter egg to players, any track previously played in the Sound Test will play when using the Gallery mode; if the Sound Test is not unlocked or not used prior to the Gallery option, then the default Menu music plays. Additionally, if the track played does not loop (such as "Opening" and "Rare Trophy!"), then the last track played that does loop in the Sound Test plays; if no such track was played, then the Menu music plays.
In Super Smash Bros. Brawl
Brawl's gallery feature is conceptually identical to Melee's, though it hosts a variety of differences compared to Melee's incarnation. Brawl's trophies feature two games of appearance for trophies, compared to Melee's one; in addition, trophies are instead grouped by "pages" instead of a singular "list", with these pages either arrangeable via "Series", which arranges them by universe, or "By type", which lists the pages by types (such as Fighter, Fighter-related, etc.). Unlike the previous game, there is no way to list all the trophies in alphabetical order.
Brawl also takes count of how many copies of one trophy the player has; while this was present in Melee, the presence of the Diorama in Brawl makes this function slightly more useful.
Brawl's gallery plays its own track, "Trophy Gallery", when it is accessed, and Melee's Sound Test easter egg did not return.
In Super Smash Bros. 4
Super Smash Bros. for Nintendo 3DS's gallery feature combines a number of Melee's and Brawl's galleries. By default, trophies are arranged in a list that is sorted chronologically, with the newest trophies being displayed first; Brawl's categorisation, however, does return, allowing players to sort trophies either by series or by category, such as Fighter, Fighter-related, Item, etc. Players are again given information on how many trophies they have.