Smash Tour is the Wii U-exclusive board game-type mode in Super Smash Bros. for Wii U.
Introduced in the 2014 Wii U release, Smash Tour places up to four players on a large board. Players move around it, collecting fighters, stat boosts, and other advantages before entering battles triggered by landing on particular spaces. The fighters gathered during the tour form each player’s temporary team.
The mode was designed as a multiplayer-focused alternative to a standard sequence of matches. Its board size, turn count, and some customization options can be adjusted, giving each session a different rhythm. The battles themselves still use Smash’s familiar platform-fighting rules, but the board determines which fighters and bonuses are available.
Smash Run is the comparable exclusive mode from the Nintendo 3DS version, not Wii U. StreetSmash is also associated with the 3DS and uses StreetPass, while Spirit Board belongs to Super Smash Bros. Ultimate. Smash Tour is therefore the single canonical answer.