Yes indeed. Those are good choices.

Deadly Creatures. Play that game.

Fragile dreams: Ruins of the moon. please play this game.

A boy and his blob
Opoona
Spectrobe: Origins
Battalion Wars 2

These are all great games, you can find them real cheap and not very well known.

I own 4 out of 5 of those games and I have sadly only played BW2 (I don't have opoona)

I'll get them all though eventually

Does Mushroom Men count? I have enjoyed the game thoroughly

Art of Balance seems cool

That Harvest Moon game sounds like a terrible grindfest

Dewwy I remember way back... I think from same developers as Elebits. I think they stopped trying with Wii after that.

It is unbelievable to me how many average under marketed games were made for the Wii that got lost amidst all the truely shovel ware that landed on the system. I actually bought some of the crappiest games I have ever tried on Wii because I was so willing to give new games a shot.

Mercury Meltdown, Kororinpa (tilt games, great)
Elebits - novel gameplay
Let's Tap - Really novel and fun game
Ivy the Kiwi - great overlooked game
Fishing Resort - extremely deep fishing game
Lost in Shadow - Unique platformer
Sakarua Wars: So Long my Love - Awesome romance SRPG mash-up. Only game of this type ever to make it out of Japan
Sky Crawlers: Innocent Aces - Best flight Sim - good luck finding it now.
Tenchu 4 - stealth ninja action
Project Zero 2 (in PAL regions) - horror
The Calling (horror)
Cursed Mountain (novel horror on a mountain with tibetan monk ghosts)
Ghostbusters
Trackmania - intense racer - build your own tracks
Prof. Wolfe's Gravity (physics puzzler)
Sam & Max (1&2), Broken Sword, Secret Files (1&2), Tales of Monkey Island (1-5 on Wiiware) - Point and click gold


Already mentioned I second:
Opoona
Munchables
Mushroom Men
A Boy and His Blob
Rogue Trooper
Fragile

Other more 'known':
Prince of Persia - Forgotten Sands
Lara Croft: Anniversary
Go Vacation

90% of that list is the type of game I said I didn't want on the list in the first post. I'm not looking for games that someone thinks didn't do well enough, games that someone thinks were underated, or games that you feel more people should have played.

Most of  those games got a good amount of media coverage regardless of whether or not they suceeded. In fact those are some of the biggest named 3rd party titles to come out on the system.

I'm looking for games that received next to no coverage but were really good and hardly anyone knows they exist. Games like Kororinpa and Trackmania.

Kororinpa. Most people will take a look at it and not give much more thought to it.

Trackmania

Does Nyxquest count? It was a hell of a fun game that showed good use of the motion. It's kinda short though.

There was news of it that came out which many thought to be Kid Icarus and then it was released and all hopes were shattered, but then soon after that's when Nintendo announced Kid Icarus.

Not being argumentative, but that Harvest Moon game you listed is a pretty well known title (certainly one I'd heard of).  I mean, Harvest Moon is a relatively large series, it sold double what Sin & Punishment did (which, for reference, I had never heard of).  I'd say Trackmania is a pretty well-known franchise as well.  It's all relative.