Digimon World, so many unique features built into one game. Not only taking care of digimon but an age system as well as day/night systems for a PS1 game is incredible. As well as city building and many more features.

Penguin Adventure, classic Tomb Raider, Parasite Eve 1, isometric Ys games, Ring of Red, Onimusha 1-3, Shadow of the Colossus, Oddworld Stranger's Wrath, Valkyria Chronicles, The Last Guardian, and Tears of the Kingdom among others.

A lot of what they do is done in other games, but they were innovative and mixed things up in interesting ways that made them particularly unique to me compared to anything I experienced that came before or after them.

Time to add Dreamcast to NSO and put this on there. 

I wish I had an easy way to experience this wild game, but I do not think I have the patience. 

Kunitsu-gami: Path of the Goddess is a game that stands out to me as quite unique; part RTS, part tower defense, part melee action game, all stylised after Japanese Shinto mythology. Brilliant game too.

This was going to be my example. Weirdest game I have ever experienced and I loved it. Sega really put out some unique and amazing bangers on the Dreamcast. 

Someone else mentioned Blast Corps too, another great example.

Crypt of the Necrodancer and Rocket League

Kings field?
Well okej there is kings field 2 3 4 xd

Tokobot is a bit like pikmin,tried that one yet?

Death stranding

First game to come to mind is Papers Please. That is one strange game.
Odama is another one, but I have not played that thing.

Metroid Prime
Minecraft
Traditional 3D Zelda's
Kirby Air Ride (City Trial mode)
Resident Evil 7 & 8 (in VR)
Red Steel 2
Elebits/Eledees
Super Smash Bros (if you imagine two certain copycat games don't exist)
Paper Mario
Luigi's Mansion
Pokémon Go
Pokémon Snap
Donkey Kong Bonanza
Lemmings
Worms (Hogs of War is 3D so it doesn't count)
Slender man (unless there are PC clones made by people in their bedrooms)
Portal
Bomber Man
Bubble Bobble
E.T