Is there any thing that is more powerful than this artifact?

The Tablet of Order and Chaos - http://marvel.wikia.com/Tablet_of_Order_and_Chaos

Any artifacts that are more powerful than this artifact?

Also are there any cosmic entities that could beat someone with this artifact?

Lord of Nightmare's Shovel!

It says outright on the page that "The Tablet of Order and Chaos is one of the most powerful mystic artifacts in the Earth-616 universe", therefore it stands to reason that yes, there have to be artifacts more powerful than this.

Yes, it's called the Tablet of the Tablet of Order and Chaos. See this is how fiction works. There's always something stronger, because I can just make something up.

Interesting

I call mine the pencil and eraser.

That sounds like a much more convenient name, yes. I think I'll use it, it's kind of catchy. Peeennn-suuuulll.

The correct pronunciation for my new word is (ˈpensəl). I think I'll put it in the dictionary, so if you see it, it's because I put it there. ;)

The thing can't be all that powerful. Apparently Spider-man defeated Mysterio, who had the entire thing. So unless Mysterio is dumber than a box of bricks that have just been mind raped by the Mind Gem, the thing obviously has an easily exploitable weakness.

I'm going to say there have to be some better items, like the Infinity Gems, or probably something from Doctor Who or a Star Trek novel. They have plenty of crazy stuff in those universes.

I meant like anything in the Marvel or DC universe! Sorry!

Hm. That doesn't sound right to me. Well, you're the one who made it.

Yes, the stench from your breath.

@clanslayer: living tribunal and TOAA would scoff it off.