Toribash is quite possibly the best competitive fighting game I have ever played due to it's unique method of controlling your actions. It's almost entirely unheard of tho.

Plants vs Zombies on PC.

Great, unique, iconic, still fun to play. Its biggest achievement: I have brought a lot of people into the hobby by making them play this as their first video game and there wasn't a single one not having fun. Tower defense is as a whole an underrated genre if we talk about the best games of all time. It also is a game that offers achievements that add a lot to the gameplay by challenging you to change your tactics.

They of course had to make the second one mobile only and on top ruin it with microtransactions. :( Greed is why we can't have nice things.

Pirate Trainer & Uru: Ages Beyond Myst

I remember trying Pirate Trainer in a Nvidia game booth when VR was new. It was incredible, years later I get a VR headset and its the free game. I don't understand how no one has improved upon it.

Uru was the first puzzle game I thought struck a good balance between physical and mental puzzles. They were set at a level that felt challenging but not impossible and laid out so you alternated really nicely. Myst Online actually went backwards in this

Trog.. I played that game for days

Freespace 1 & 2 deserve a mention here. Old games, so smaller in scope than modern games. But I feel they can compete still.

It just occurred to me that Death Really (1995) would deserve to be talked about as well, it's just an incredible little game.