One thing that keeps my Wii U hooked up is that even though a lot of its library was later ported elsewhere, the Wii U versions are still better. This is bizarrely true even for first-party Nintendo games: the Switch version of Mario 3D World is sped-up and twitchy-feeling compared to the Wii U version, and Captain Toad and PIkmin 3 are far preferable with their original control schemes.
Even ignoring the touchscreen and the second-screen stuff, I said on some other thread recently that the Wii U controller is big and heavy and deliberate-feeling when you press a button, and some games just feel better on that controller. Sonic Lost World was the example I used, but there are many.
It’s also a totally fine way to play GameCube and Wii games over HDMI. I know there are better options out there, but actually the various homebrew loaders available can do a good job of getting you excellent image quality, widescreen modes etc. And it’s so easy.
Tokyo Mirage Sessions #FE is worth playing, if you have any interest in that style of game (persona/smt/etc style rpg). I think it got a switch port, but I don’t remember hearing much about how that port came out.
Sadly, the answer really is not much. Not much that’ll provide meaningful “good” experiences anyways. Lots of bizarre crummy tiny games for someone interested in trash. I’ve spent a few nights checking out some awful games for a few mins each but I never leave being especially satisfied. Some of my actual faves that haven’t made it off the console/are still the best on it are Yoshi’s Woolly World, Pushmo World, NES Remix 1 & 2, Fast Racing NEO, those Zeldas you mentioned, and using Priitendo makes the original Super Mario Maker and Splatoon worth some visits as well. Ace of Seafood, Bayonetta 2, The Wonderful 101, Super Mario 3D World, Pikmin 3, and Donkey Kong Country: Tropical Freeze are nice if you don’t have them elsewhere. Other notable games that I don’t like so much are Paper Mario: Color Splash and Star Fox Zero. Nintendo Land and Game & Wario could be worth picking out if you plan on turning on the console with some buds for whatever reason. It really is just a Nintendo machine in the end. If you’re not interested in some first-party Nintendos you can find pretty much all other good games on there on Steam or the Switch.