You can find the base game and all DLC directly on the Nintendo eShop. For the best value, the bundle includes the base game plus both the Fresh Flavors and Just Desserts packs.
The most significant addition in the is the "Ranked" and "Daily Run" modes. Boomerang Fu Switch NSP -DLC Update- -eShop-
If you are using a legitimate copy from the eShop: The DLC costs roughly $4.99 - $7.99 (depending on sales) and effectively doubles the content. Without it, the game feels like a demo. You can find the base game and all