As of right now my top 3 multiplayer games are: CS:GO, Smash Ultimate, TF2.
My top 3 singleplayer games are: Windwaker, Portal 2, Hotline Miami 2.
And my favourite "coop" with friends games are: Terraria and Minecraft.
I don't really know how to split "favourite" from "best", but I guess the singleplayers are like the favourites.