I personally think PlayerUnknown's Battlegrounds (PUBG) is one of the best game of 2018 with more than 50 Million active players.
Fortnite? I mean I'm not a fan, but the numbers say so, it has most twitch views and is popular even on Switch! https://www.eneba.com/blog/fortnite-was-the-most-played-game-for-nintendo-switch-in-2018/
And what makes you think a single answer is going to be possible, or that it would even be relevant in a development forum? Is your intention to try to clone it or something?
Best game in 2018? Canasta.
And what's wrong with a good old-fashioned card game? It involves interacting with actual people in actual reality. It involves thinking instead of just frantically reacting. And there is lots of interesting conversation. You also don't have to pay for downloadable content and there are no in-app purchases.
FIFA 18 for me.
RE Canasta - I left out the best reason. It's platform independent. You can play it on any type of table, or even on the floor ^_^
I think PlayerUnknown's Battlegrounds (PUBG) is one of the best game of 2018
Far Cry 5
2018 is bad year of games actually
Personally I find that an opinion, no matter who gives it, is pretty nuch worthless without something to back it up.