Pikmin 3 originally released back for the Wii U in 2013 and was one of the best games at taking advantage of the Wii U GamePad. A follow-up was announced a number of years ago now and was supposedly at the time not far away from completion, but evidently they must have decided to change course behind the scenes as nothing has come from that. Instead, Nintendo is now re-releasing Pikmin 3 on the Wii U as Pikmin 3 Deluxe and a demo is now available for the game.
As of right now, you can get a demo for Pikmin 3 Deluxe on the Nintendo Switch eShop. The best way to access this is to search for Pikmin 3, which is likely on the main screen of the eShop, and select it. From here you can not only pre-order the game, but also download the demo.
This demo actually starts from the very beginning of the game just as if you were starting up the full game. This is where you get introduced to the trio of characters and the Pikmin as they start their journey to get home.
What is especially interesting here is that Nintendo revealed that progress from this demo will carry over into the full release when it comes out at the end of the month. In addition, completing the demo will also unlock the new Ultra-Spicy difficulty from the very beginning in the full release, so Pikmin veterans will probably want to take advantage of that.