Welcome to the Nintendo Club, Henke! Cake and colas are in the back!
Two games to get besides Mario and Zelda?
Fast RMX. It's pretty much F-Zero in all but name, with Wipeout style aesthetics thrown into the mix. If mention of those two games excites you, you really have no excuse not to get it.
Blaster Master Zero!
edit: As far as big game sales go, it all depends on when you hit it up. Last week, I guess they had a Halloween spree going on, because there were about 15 games or so on sale for as much as 50% off. Right now, I think there are only three discounted at, like you said, 33%.
One good thing to keep in mind is that there is no regional lock on the Switch. You could make an account regioned for the US or Japan, and get demos and games exclusive from there if you want.