Biome is a 3D game in which you find blobs and consume them which in turn increases your size and lethality. You must also run away from your bigger opponents because they are able to eat you which causes you to die. 3D Agar
Hordes.io is an online multiplayer 3D fantasy game in which your character flails around in an environment of your choosing and fight other scary characters by yourself or with your team.
Agar Wtf is a widely popular 2D online action game. In this game, players command a "cell" which looks like a ball.
Do you recall the generic minesweeper game that was pre-installed in Windows operating systems? This is the multiplayer version of that game but in a slightly different way.
BigHero.io is the hack n slash style game in which you control a character from a top-down view and must kill everything in sight. In this world its win or lose there is no other option so make sure you time your attacks accordingly to hit your enemies with your weapon before they hit you.