Gather! New Leaguers (Japanese: あつまれ！ ニューリーガー) is the first set in the Pokémon Tretta Fes series, and the sixth set overall. It features 48 Tretta.
Gather! New Leaguers marks the start of a new Pokémon Tretta series, featuring graphical changes to the user interface on all upgraded Pokémon Tretta machines, and changes to the illustrations and layout on the Tretta themselves. Several articles, such as Pokémon and move names on Tretta, as well as modes and instructions during gameplay, had English translations for the first time. The overall theme for this series is of a festival, shortened to "Fes", reflected in the appearance of the locations present in the game: Forest, Waterfront, Field, Ruins, and Beach.
The Legend-class Tretta for this set features Mewtwo, with all other standard Tretta colored a darker shade of red called "volcano red". The "Home and Away" mechanic introduced in Search for the Legendary Pokémon! is renamed Fervor (Japanese: やる気) in this set, thought the principle remains the same: using Tretta from the latest set will increase the chances of Pokémon being in a "Good Condition", while older Tretta risk the Pokémon being in a "Bad Condition", resulting in a boost or drop in stats respectively. The Secret Ticket mechanic was also officially announced with this set, in which a handful of recently released promotional Tretta would unlock a special ticket after use in any game mode. This ticket would allow them to summon a Pokémon with a beneficial effect during future gameplay.
Gather! New Leaguers introduces Pair Battle and Catch (Japanese: ふたりでゲットGet in Pair) mode, which includes two-player elements that can increase chances of dealing more damage or evading attacks in Battle Mode, and increase the chances of selecting a more effective Poké Ball in Catch Mode. The core gameplay remains largely similar however. Another new play mode, Extra Campaign (Japanese: エクストラキャンペーン), was introduced shortly after on August 24, 2013. Unlike other game modes, Extra Campaign could not be played without a Tretta Report, and after dispensing a random Tretta, began a battle against a random team of Pokémon that included a Legend-class Pokémon. The sole purpose of Extra Campaign was to capture the Legend-class Pokémon, and if the player failed to do so, any progress made was saved on the player's Tretta Report and carried over to the next attempt. Extra Campaign ran for the entirety of the Pokémon Tretta Fes series, and made three Pokémon available for capture for limited periods of time: Reshiram, Zekrom, and Kyurem. All of these Pokémon could be selected as an Extra Attacker at special events, and eventually in normal gameplay from the Chespin! Fennekin! Froakie! set.
This set also adds the Weekly Bonus (Japanese: ウィークリーボーナス) feature, which provides a helpful boost in one of the three modes during gameplay for one week. See the Weekly Bonus section for more information.