1-2 Switch site came up and with this there are 18 mini-gameplay videos of the 28 total mini-games that have been confirmed.
There are an additional 10 missing mini-games, but they are hinted in the image below.
Click the youtube links or just visit the site: https://www.nintendo.co.jp/switch/aacca/index.html
Sword Fight: https://www.youtube.com/watch?v=-PYBMtwH_iw
Wizard: https://www.youtube.com/watch?v=prz6YliFolg
Telephone: https://www.youtube.com/watch?v=o7g0Y2b977U
Shaver: https://www.youtube.com/watch?v=FNwdDkfRiUU
Runway: https://www.youtube.com/watch?v=XWOZtsBQIRA
Soda: https://www.youtube.com/watch?v=RCUmtkMkPJo
Baby: https://www.youtube.com/watch?v=42FPUcC8RjM
Joy-Con Rotation: https://www.youtube.com/watch?v=drhChHv_HuI
Liar Dice: https://www.youtube.com/watch?v=Heg2x50O6cg
Beach Flag: https://www.youtube.com/watch?v=m30aPiQEBew
Quick Draw: https://www.youtube.com/watch?v=K8amOnYVZR0
Milk: https://www.youtube.com/watch?v=HdE9kygpwls
Eating Contest: https://www.youtube.com/watch?v=oZftMhIB7nU
Count Balls: https://www.youtube.com/watch?v=3gxLMldRXAg
Samurai: https://www.youtube.com/watch?v=pmGPWpDWZNs
Ping Pong: https://www.youtube.com/watch?v=8XOcoaqIJCY
Safe Cracker: https://www.youtube.com/watch?v=5hPibSI8YDo
Copy Dance: https://www.youtube.com/watch?v=uQF3vbHtGBE
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Can you guess the 10 mini-games left?
Extra ones so far:
Dish Spin
Baseball
Zen
Sailor
Treasure Box
Boxing Gym
Air Guitar
Sword Fight
Gorilla
Fake Draw