Nothing like Nibbler really, other then a snake/worm thingy that grows. Nibbler is all about speed in a confined space, with only yourself as your worst enemy.
I haven't played it yet but slither.io looks really fun and appears to have a very classic feel to it. My kids have played it some - maybe your post will get me motivated to sign up and play!
Super fun, and wildly addictive. First game in a long time where I've lost track of time.
Was riding at #1 for a while this morning:
For those that haven't played, comparing this to Nibbler are like apples to oranges. The only thing similar is the eating of dots/pellets for growth. There is quite a bit of strategy involved, especially in an unpredictable multiplayer environment.